List of interesting problems by -Morass-

Interesting problems.md

Table of contents

1. Алгоритм Ахо-Корасик
2. Поиск в ширину (BFS)
3. Поиск в ширину по сетке
4. Длинная арифметика
5. Бинарный поиск
6. Битовые операции
7. Битовые множества (bitset)
8. Алгоритм Блоссома
9. Мосты
10. Полный перебор
11. Барицентр
12. Раскрашивание
13. Комбинаторика
14. Конструктив
15. Поиск в ширишу (DFS)
16. Работа с цифрами
17. Алгоритм Дейкстры
18. Разделяй и властвуй
19. Динамика
20. Cистема непересекающихся множеств (СНМ)
21. Функция Эйлера
22. Цикл Эйлера
23. События
24. Факторизация
25. Дерево Фенвика
26. Быстрое преобразование Фурье
27. Потоки
28. Алгоритм Флойда — Уоршелла
29. Теория игр
30. Геометрия
31. Графы
32. Жадность
33. Хэши
34. Шахматы
35. Реализация
36. Формула включений-исключений
37. Интерактивные задачи
38. Задача Иосифа Флавия
39. Алгоритм Кнута — Морриса — Пратта
40. Задача LCA (наименьший общий предок)
41. Наибольшая общая подпоследовательность
42. Задача поиска наибольшей увеличивающейся подпоследовательности
43. Паросочетание
44. Матрицы
45. Экспонента матрицы
46. Поток минимальной стоимости
47. Поиск медианы
48. Встреча в середине (Meet in the middle)
49. Алгоритм МО
50. Магический квадрат
51. Теория чисел
52. Последовательности OEIS
53. Оффлайн вычисления
54. Палиндромы
55. Прошедние контесты
56. Сопоставление с образцом
57. Перестановки
58. Персистентные деревья отрезков
59. Ро-алгоритм Полларда
60. Степень
61. Препроцессинг
62. Проверка на простоту
63. Очередь с приоритетами
64. Вероятность
65. Рекурсия
66. Задача RMQ (минимум на отрезке)
67. Структура данных rope
68. Компоненты сильной связности
69. Дерево отрезков
70. Последовательности
71. Решето
72. Моделирование
73. Сортировка
74. Остовное дерево
75. Быстрый алгоритм поиска кратчайшего пути (SPFA)
76. SQRT-декомпозиция
77. Работа с STL
78. Строки
79. Суффиксный массив
80. Пересечение множества отрезков (заметающая прямая)
81. Тернарный поиск
82. Топологическая сортировка
83. Декартово дерево
84. Дерево
85. Префиксное дерево c битами
86. Префиксное дерево cо строками
87. Задача коммивояжёра
88. Два указателя
89. Z-функция
90. Задача 2-SAT

Алгоритм Ахо-Корасик

http://codeforces.com/contest/696/problem/D 8

http://www.spoj.com/problems/AHOCUR/ 5 //Aho-Corassic + DP

Поиск в ширину (BFS)

11312 UVA (3)

11392 UVA (4)

http://codeforces.com/contest/653/problem/E (6)

http://codeforces.com/contest/769/problem/C 5 //FL:ODD/**** | bfs+greed NICE

10968 UVA (3) //EASY + NICE (bfs withot <=2 nodes)

http://codeforces.com/contest/796/problem/D (3) //NICE+EASY ... print visited in bfs (not par)

10888 UVA (4) //VERY NICE — but not main technique ... ++ DP /or/ MCMF

http://codeforces.com/contest/821/problem/D (5) //VERY NICE — Consider only points not GRID

http://www.spoj.com/problems/DIGOKEYS/ (4) //Easy [Nice problem — weird statement]

http://www.spoj.com/problems/SPIKES/ (3) //Easy bfs (# of 's' * 2)

http://www.spoj.com/problems/MULTII/ (4) //VERY NICE: BFS over numbers (K*10+d)%N

Поиск в ширину по сетке

10977 UVA (3)

928 UVA (3)

13116 UVA (4)

314 UVA (3)

11487 UVA (4)

5622 LA (7)

11931 UVA (5)

http://www.spoj.com/problems/KNMOVE/ 3 //simple knights

http://www.spoj.com/problems/SERGRID/ 3 //almost classical

http://www.spoj.com/problems/NAKANJ/ 3 //Classical chess — KNIGHT

http://www.spoj.com/problems/PUCMM223/ (4) //NICE (but not many languages) — 2 moving [x][y]

http://www.spoj.com/problems/SPIRALGR/ (4) //NICE (not typical) [SIEVE]

http://www.spoj.com/problems/DCEPC706/ (4) //NICE — travelling outside

Длинная арифметика

11645 UVA 4

11375 UVA 3

http://www.spoj.com/problems/MINNUM/ 3 // BIG/9+!!(BIG%9)

10844 UVA 4 //Bell numbers + big (might be slightly slow!)

http://www.spoj.com/problems/NITT2/ 2 //Divisibility by two constants

Бинарный поиск

http://codeforces.com/contest/729/problem/C 3

http://codeforces.com/contest/714/problem/D 8

13150 (UVA) 4

http://codeforces.com/contest/749/problem/D 5

11692 (UVA) 4

11516 (UVA) 3

http://codeforces.com/contest/760/problem/B 3

http://codeforces.com/contest/675/problem/D 4 //dunno — solvable with treap

http://www.spoj.com/problems/NDS/ 4 //BS over LIS

http://www.spoj.com/problems/VECTAR4/ 3

http://codeforces.com/contest/767/problem/D 4 //NICE

http://codeforces.com/contest/627/problem/D (7) //with dp — NICE

http://codeforces.com/contest/779/problem/D (3) //NICE + EASY

http://www.spoj.com/problems/CNTINDX/ (4) //Map+BS === OK

13177 UVA (3) //BS over answer == OK

http://codeforces.com/contest/801/problem/C (3) //BS + SUM -EASY

http://codeforces.com/contest/803/problem/D (3) //BS by answer

http://codeforces.com/contest/807/problem/C (3) //Or math

http://codeforces.com/contest/818/problem/F (4) //NICE — Live VS Clique

http://codeforces.com/contest/845/problem/E (5) //VERY NICE — min(X,Y) .. add time, repeat

http://www.spoj.com/problems/MATHLOVE/ (2) //BS + Gaus (or otter ways)

http://www.spoj.com/problems/SABBIRGAME/ (3) //Binary search over answer ::max(0,ANS)

http://codeforces.com/contest/846/problem/D (4) //BS+Precalculation OR 2D-RMQ

Битовые операции

11659 UVA (4)

11535 UVA (4)

http://codeforces.com/contest/779/problem/E (5) //NICE + Parsing

http://www.spoj.com/problems/EC_CONB/ (1) //reverse numbers

http://codeforces.com/contest/769/problem/D (4) //freq + brute-force

http://www.spoj.com/problems/HAP01/ (2) //builtin_popcount

Битовые множества (bitset)

http://codeforces.com/contest/754/problem/E 6

http://www.spoj.com/problems/UCBINTC/ 5 //polymul with bitset

Алгоритм Блоссома

11439

Мосты

http://codeforces.com/contest/732/problem/F 7

http://codeforces.com/contest/700/problem/C 7

http://www.spoj.com/problems/EC_P/ (3) //bridges ONLY

http://www.spoj.com/problems/SUBMERGE/ (3) //Direct articulation

http://www.spoj.com/problems/GRAFFDEF/ (5) //Bridge tree

Полный перебор

UVA 12169 (2)

http://codeforces.com/contest/725/problem/C 4

http://codeforces.com/contest/725/problem/E 6

http://codeforces.com/contest/724/problem/B 3

11961 UVA (2)

11898 UVA (4)

11659 UVA (4)

http://codeforces.com/contest/753/problem/C 7

11699 UVA (4)

11548 UVA (3)

11471 UVA (5) //With dynamic programming

http://codeforces.com/contest/698/problem/D 8 //with geometry

11206 UVA (6) //4^20 (but somehow passes)

11214 UVA (6) //Úvaha + pruning

11127 UVA (4) //Simple dfs [just realize you can do so]

http://www.spoj.com/problems/BOKAM143SOU/ (3) //just implement for-cycles

http://www.spoj.com/problems/BLOPER/ (4) dfs with little pruning

13173 UVA (3) //just brute-force + branching

http://codeforces.com/contest/799/problem/D (4) //VERY NICE [only top 34 needed] — trick with 2 [~20]

10890 UVA (4) //Simple brute-force times out, but with simple pruning AC (answer detection

http://codeforces.com/contest/813/problem/B (3) //All*All (BF) care for overflow! NICE & EASY

http://codeforces.com/contest/817/problem/C (3) //Check S+Constant (NICE!)

10732 UVA (2) //Brute-force passes .. just don't trust them O(N^2)

10748 UVA (5) //VERY Nice (knights have K^2 moves not 8^K)

http://codeforces.com/contest/818/problem/D (4) //NICE for each 'A' check all remaining (max SQRT)

http://codeforces.com/contest/834/problem/E (5) //NICE — hard to imple: all 11122...999 OK

http://codeforces.com/contest/839/problem/E (5) //NICE! Max-Clique

http://www.spoj.com/problems/JHAGIRLS/ (4) //Efficient — or store output in array

http://codeforces.com/contest/846/problem/B (3) //Brute-force

http://www.spoj.com/problems/ALONE/ (4) //Generate everything <10^15 [NICE]

Барицентр

http://codeforces.com/contest/715/problem/C 9

http://codeforces.com/contest/741/problem/D 8

13164 UVA (7)

http://codeforces.com/contest/752/problem/F 5

http://codeforces.com/contest/766/problem/E 6

http://codeforces.com/contest/833/problem/D 7 //Very nice — hard (thinking + imple) + FW

Раскрашивание

http://codeforces.com/contest/741/problem/C 6

11331 UVA (4)

http://codeforces.com/contest/664/problem/D 4

Комбинаторика

12001 UVA (3)

12034 UVA (4)

11719 UVA (5)

11798 UVA (5)

11282 UVA (4) //dearrangement

11174 UVA (4)

http://codeforces.com/contest/666/problem/C 7

http://www.spoj.com/problems/JOKER1/ 3 prod(Ai-i)

http://www.spoj.com/problems/ANTP/ //4

http://codeforces.com/contest/645/problem/E (5) //formula: A[i]=Sum(A)+1

http://www.spoj.com/problems/SPCE/ (5) // N^{K-2}*Prod(comp_size)

http://codeforces.com/contest/785/problem/D (5) // F'(' C"(+)-1","("

13184 UVA (3)

http://codeforces.com/contest/816/problem/D (5) // Observation

13214 (4) //OEIS? : C(N+M-2,N-1)

http://codeforces.com/contest/844/problem/B (2) //Easy — pro prvaky

http://www.spoj.com/problems/JOSWAP/ (3) //Frequence array

http://www.spoj.com/problems/UCV2013E/ (4) //NICE&EASY: Choose steps to direction

http://www.spoj.com/problems/PARCARD1/ (4) //Partition function (raw)

http://www.spoj.com/problems/GOODB/ (2) //Easy (NICE): Choose [order]

http://www.spoj.com/problems/LOOPEXP/ (4) //A000254/N!

http://www.spoj.com/problems/DTPOLY/ (5) //DP might work too

http://www.spoj.com/problems/DTPOLY2/ (7) //Harder version of above (NICE but hell)

http://www.spoj.com/problems/HC12/ (3) //NICE — Sort + C(i,K-1)*A[i]

http://www.spoj.com/problems/STONE2/ (4) //NICE — Mostly DP [INVERSION][FACTORIAL]

Конструктив

http://codeforces.com/contest/802/problem/H (6) //We can do "N+k" by adding a letter p+k*x+u+xx

Поиск в ширишу (DFS)

12186 UVA (3)

http://codeforces.com/contest/734/problem/E (5)

http://codeforces.com/contest/727/problem/A (3)

http://codeforces.com/contest/723/problem/E (6)

http://codeforces.com/contest/709/problem/E (6)

http://codeforces.com/contest/710/problem/E (4)

http://codeforces.com/contest/758/problem/E (8)

11323 UVA (5)

http://codeforces.com/contest/760/problem/B (3)

http://codeforces.com/contest/761/problem/E (6)

http://codeforces.com/contest/638/problem/B (3) //connect cons. letters

http://codeforces.com/contest/638/problem/C (4) //greedy idea — easy

http://codeforces.com/contest/638/problem/D (5) //spec-DAG articulatin

http://codeforces.com/contest/767/problem/C (4)

http://codeforces.com/contest/781/problem/C (5)

http://codeforces.com/contest/794/problem/D (5) //NICE! Right done dfs

http://codeforces.com/contest/802/problem/K (5) //Slightly DP-like (NICE) TREE

http://codeforces.com/contest/813/problem/C (3) //Simply 2 DFS: NICE + EASY

http://codeforces.com/contest/841/problem/D (4) //DFS while tracking "next"

http://codeforces.com/contest/845/problem/G (5) //Keep track of cycles

http://codeforces.com/contest/844/problem/E (5) //Post-Order → line, Connect i → N-2: star

http://www.spoj.com/problems/CAC/ (5) //VERY NICE! — Find all cycles in cactus

http://codeforces.com/contest/849/problem/C (3) //State search by gauss

http://codeforces.com/contest/846/problem/E (5) //NICE: DFS + some overflow logic

http://www.spoj.com/problems/KOZE/ (3) //NICE: Floods

http://www.spoj.com/problems/RIOI_2_3/ (4) //DFS /OR/ BFS /OR/ DSU [NICE][EASY][BF]

http://www.spoj.com/problems/MAKEMAZE/ (3) //EASY — Simple dfs on grid

Работа с цифрами

http://www.spoj.com/problems/PR003004/ (4) //Simple digits count

http://codeforces.com/contest/770/problem/B (3) //max num max digsum

Алгоритм Дейкстры

http://codeforces.com/contest/716/problem/D 7

12047 UVA 4

11514 UVA 4

http://codeforces.com/contest/757/problem/F 7

11338 UVA (4)

11374 UVA (4)

11097 UVA (4) //Divide to N*1000 nodes and go!

13172 UVA (5) //6*DJ per query + permutations

10816 UVA (4) //Easy Linear-Search by answer + DJ with path

http://codeforces.com/contest/827/problem/F 7 //Very nice — Even&Odd

Разделяй и властвуй

http://codeforces.com/contest/817/problem/D (5) //Very nice NlogN

Динамика

11552 UVA (3)

12172 UVA (3)

4507 LA (5)

4510 LA (5) [+ geometry]

12181 UVA (6)

http://codeforces.com/contest/729/problem/F 6

http://codeforces.com/contest/735/problem/E 9

http://codeforces.com/contest/731/problem/E 5

12030 UVA (4)

http://codeforces.com/contest/721/problem/E 7

http://codeforces.com/contest/742/problem/D 4

12040 UVA (5)

http://codeforces.com/contest/712/problem/D 5

13162 UVA (6)

http://codeforces.com/contest/743/problem/E 6

11908 UVA (3)

11932 UVA (4)

http://codeforces.com/contest/745/problem/E (7)

11806 UVA (4)

http://codeforces.com/contest/747/problem/F (5)

11843 UVA (4)

http://codeforces.com/contest/752/problem/E (5)

http://codeforces.com/contest/703/problem/E (7)

11753 UVA (4)

11725 UVA (5)

http://codeforces.com/contest/722/problem/E (9)

http://codeforces.com/contest/760/problem/F (8)

11795 UVA (3)

11654 UVA (4)

11523 UVA (5)

11404 UVA (4)

11432 UVA (4)

11451 UVA (4) //C==20 mistake in statement

11301 UVA (4)

http://codeforces.com/contest/762/problem/D 5

11361 UVA (4) //digit DP

11365 UVA (7)

11391 UVA (4) //easy+implementation

11394 UVA (3)

11218 UVA (2)

11125 UVA (4) //slightly implementation

11076 UVA (3)

11081 UVA (4) //3 string subsequences (beware of fail)

http://codeforces.com/contest/678/problem/E (5) //bitset dp + probability

http://codeforces.com/contest/766/problem/C (4)

http://codeforces.com/contest/667/problem/C (3)

http://www.spoj.com/problems/MOVIFAN/ (3)

http://www.spoj.com/problems/ORDSUM23/ (3)

http://www.spoj.com/problems/DIVSEQ/ (4) //N^3 (but better...) works fine

http://codeforces.com/contest/633/problem/F (7) //Tree dp

http://www.spoj.com/problems/ADJDUCKS/ (4) sort + pick 2-3 continous O(N)

http://www.spoj.com/problems/JLNT/ (4) //pick 0 or 2 | 1e3*5e3

http://www.spoj.com/problems/TPCPALIN/ (5) //500^3 works (3rd countable)

http://www.spoj.com/problems/COLORSEG/ (4) //50^4==OK 50^4log(N)=TLE NICE

http://www.spoj.com/problems/POWERCAR/ (3) //1e31e32 — follow rules

http://www.spoj.com/problems/INGRED/ (5) //TSP-like [reduce + go]

http://www.spoj.com/problems/BADXOR/ (4) //classical subsets

http://www.spoj.com/problems/SPCO/ (5) //64642 DP {OPT: prime O(1) + clear only half}

http://www.spoj.com/problems/WAYHOME/ (5) //NICE: 1) 1*1 b)12,1,**,2

http://www.spoj.com/problems/NFURY/ (2) //Minimal sum of squares

http://www.spoj.com/problems/GDIL/ (3) //combinatorics

http://codeforces.com/contest/791/problem/D (5) //Tree

http://codeforces.com/contest/791/problem/E (6) //V,K,X — pick any

http://codeforces.com/contest/789/problem/C (3)

13176 (4) //N^6

13179 (5) //NICE [Ath][Bth][TimeDiff]

http://codeforces.com/contest/796/problem/E (6) //NICE: NPK*K (WC can't happen!)

http://codeforces.com/contest/797/problem/E (4) //NICE: Almost BF-able (but care of low K)

http://codeforces.com/contest/793/problem/D (3) //NICE & EASY: begin/end/actual/USED

http://codeforces.com/contest/803/problem/E (4) //State search — many IF's (EASY)

http://codeforces.com/contest/805/problem/F (7) //NICE: DP on tree + fast BF + hack

http://codeforces.com/contest/808/problem/E (5) //NICE!

http://codeforces.com/contest/811/problem/C (4) //Precalculate + DP (greedy thinking)

10817 UVA 4 //Easy but slightly implementation

10859 UVA 4 //Nice — on tree .. but for a reason small constrains

10898 UVA 4 //Hash is lesser than 1e6 .. try everything

http://codeforces.com/contest/812/problem/B (3) //Not only DP, yet imho easiest ..many spec cases

http://codeforces.com/contest/813/problem/D (5) //VERY VERY NICE — N*N (none picked between a/b)

http://codeforces.com/contest/814/problem/E 5 //VERY NICE — Harder imple: Combinatorics

http://codeforces.com/problemset/problem/816/E (6) //NICE — Tree (hard 2C complexity)

http://codeforces.com/contest/837/problem/D (5) //NICE — yet kinda pain [must be iterative]

http://www.spoj.com/problems/AUT/ (4) //NICE — K is interesting ~ at most 1600

http://www.spoj.com/problems/GNYR04C/ (3) //Easy — Nice idea [Big→ Low approach]

http://www.spoj.com/problems/TIEROPE/ (4) //Process 2*L ~ otherwise pick BIG

http://www.spoj.com/problems/IITKWPCE/ (4) //Palindromes [efficiency!] — NICE!

IITKWPCD SPOJ (4) //+Slightly geometry

http://www.spoj.com/problems/LKS/ (3) //Classical knapsack

http://www.spoj.com/problems/UOFTAE/ (3) //Easy & Sympatic DP

http://www.spoj.com/problems/DCOWS/ (4) //Very NICE (sort + GO)

http://www.spoj.com/problems/FARIDA/ (3) //Easy & Sympatic ((u+1) | Price+(u+2))

http://www.spoj.com/problems/AU7_5/ (2) //EASY: dyn(n-1)+dyn(n-k-1)

http://www.spoj.com/problems/NAIVELOK/ (4) //NICE [depalindromisation]

http://codeforces.com/contest/846/problem/C (4) //With print

http://www.spoj.com/problems/CNT_LUCK/ (4) //Number (binary) dp [NICE] {ull care 0-1}

http://www.spoj.com/problems/MAY99_4/ (3) //Almost combinatoric Sub and 0/1,1/0

http://www.spoj.com/problems/GEEKOUNT/ (4) //Number dp

http://www.spoj.com/problems/MUTDNA/ (4) // N*2 (turned?) [not sure if grd poss.]

http://www.spoj.com/problems/RIOI_3_2/ (5) //VERY NICE (easy imple — Number Theory thinking)

http://www.spoj.com/problems/MAXWOODS/ (3) //NICE [EASY][GRID]

http://www.spoj.com/problems/DIEHARD/ (3) //Easy — prolly solvable by greedy (but dp is easier)

http://www.spoj.com/problems/DCEPC810/ (4) //VERY VERY NICE — Subsequence 2pointers+2bools

http://www.spoj.com/problems/EQ2/ (4) //NICE: Digit + Carry (from back) — iff-party

Cистема непересекающихся множеств (СНМ)

http://codeforces.com/contest/723/problem/F 7

13153 UVA (5)

13169 UVA (3)

11987 UVA (3)

11474 UVA (4)

http://codeforces.com/contest/687/problem/D 6

http://codeforces.com/contest/680/problem/E 7 //+precalculation/brute force

http://codeforces.com/contest/766/problem/D 5

http://www.spoj.com/problems/LEXSTR/ (3) //Nice na stringu

http://codeforces.com/contest/805/problem/C 3 //NICE (dijkstra like :P)

http://www.spoj.com/problems/IITKWPCI/ (3) //VERY NICE

http://www.spoj.com/problems/FRNDCIRC (3) //Classical DSU (NICE for practice)

http://www.spoj.com/problems/FOXLINGS/ (3) Easy — just renumbering

http://www.spoj.com/problems/NITTROAD/ (4) //Process from back

http://www.spoj.com/problems/SHAHBG/ (2) //DSU not needes (simulated by array)

Функция Эйлера

http://www.spoj.com/problems/NAJPWG/ 4 //Gauss-Euler

http://www.spoj.com/problems/DCEPC12G/ (5) //Do what is written there

http://www.spoj.com/problems/INVPHI/ (5) //Inverse euler

http://www.spoj.com/problems/ETF/ 3

http://www.spoj.com/problems/TIP1/ (4) //Phi + perms

http://www.spoj.com/problems/DCEPCA03/ (3) //Phi + Reduce cycles: PPrevixP2-P^2

Цикл Эйлера

http://codeforces.com/contest/789/problem/D //Adj EG + Self/everything

События

http://codeforces.com/contest/747/problem/C 3

11776 UVA (3)

11134 UVA (3)

Факторизация

12005 UVA (7)

12062 UVA (6)

11960 UVA (3)

http://www.spoj.com/problems/FACTCG2/ (3)

http://www.spoj.com/problems/FACT0/ (4)

http://codeforces.com/contest/546/problem/D 5

http://codeforces.com/contest/222/problem/C 6

http://www.spoj.com/problems/COMDIV/ 3

http://www.spoj.com/problems/SINEGGS/ 3

http://www.spoj.com/problems/BDOI16B/ 4

http://www.spoj.com/problems/HG/ 4 //Map == OK

11099 UVA (3) //factor + recursion

13194 UVA (3) //factorize+generate /or just check

13191 UVA (6) //Pollard-Rho

http://codeforces.com/contest/818/problem/E (4) // Efficient + Two Pointers

http://codeforces.com/contest/831/problem/F (6) //MAGIC

http://codeforces.com/contest/839/problem/D (4) // Combinatorics + IE

http://www.spoj.com/problems/SAS002/ (5) //Find all divisors (big numbers)

http://www.spoj.com/problems/GCDS/ (4) //Lowest unused prime

http://www.spoj.com/problems/IITKWPCF/ (4) //Nonprime divisors of N/2

http://codeforces.com/contest/851/problem/D (4) //Properties of GCD + factor: NICE

http://www.spoj.com/problems/PTIME/ (3) //Low bounds — check each prime independently

Дерево Фенвика

http://codeforces.com/contest/707/problem/E 7 [2D]

http://codeforces.com/contest/749/problem/E 8

http://codeforces.com/problemset/gymProblem/101055/D 5 [2D]

11240 UVA (4)

http://codeforces.com/contest/669/problem/E 5 //fenwicks — sparse

http://codeforces.com/contest/777/problem/E 4 //MAXIMUM

http://www.spoj.com/problems/TULIPNUM/ 4 //inc — 1 nor+num|sum(A[B],A[E])

http://codeforces.com/contest/799/problem/C 3 //MAX FW (but possibly easier?)

http://codeforces.com/contest/831/problem/E 4 //MAP to get ORDER — FW == LIST

http://www.spoj.com/problems/SAS001/ (4) //Nice — number of inversions + 2P

http://www.spoj.com/problems/TPGA/ (4) //NICE — Lesser*(N-i-1)!

http://www.spoj.com/problems/SGIFT/ (4) //BS works too

http://www.spoj.com/problems/SUMSUM/ (5) //Bit-by-Bit cnt 0/1

http://www.spoj.com/problems/AKVQLD03/ (3) //Classical fenwick — easy

http://www.spoj.com/problems/ZIGZAG2/ (6) //Very nice — FW + BS + DP

http://codeforces.com/contest/849/problem/E (7) //2D Fenwick / ST+TP [NICE]

http://www.spoj.com/problems/CRAYON/ (5) //VERY NICE [2*FW — begin + end]

http://www.spoj.com/problems/NITT8/ (4) //Norm. + Store indices in MAX-Fenwick [REVERSE] [VERY NICE]

http://www.spoj.com/problems/DCEPC705/ (4) //NICE! Sort + Fenwick

Быстрое преобразование Фурье

http://www.spoj.com/problems/TSUM/ 5

13182 UVA 5 //ACTG hamming

http://codeforces.com/contest/827/problem/E (8) //MAGIC

Потоки

http://www.spoj.com/problems/FASTFLOW/ 3 //simple flow

http://codeforces.com/contest/808/problem/F 6 //NICE — nontrivial (max matching with bigger flows)

Алгоритм Флойда — Уоршелла

13211 UVA (5) //NICE — FW adding states

http://www.spoj.com/problems/ROHAAN/ (3) //Classical

Теория игр

11859 UVA 4

11863 UVA 4

11892 UVA 3 //Probably solved by many

11534 UVA 5

http://www.spoj.com/problems/VECTAR11/ 4 //Nsqrt(N) passes [with break]

http://codeforces.com/contest/768/problem/E (4) //NICE — Grundy

http://www.spoj.com/problems/SYNC13C/ (4) //2*DP {maybe not seeing sth}

http://codeforces.com/contest/787/problem/C (4)

http://codeforces.com/contest/794/problem/C (3) //Find optimal strategy: choose back/front

http://codeforces.com/contest/794/problem/E (5) //NICE Find stategy: Even/Odd

http://codeforces.com/contest/812/problem/E (7) //Advanced NIM strategy

http://www.spoj.com/problems/GAMEMVS/ (4) //Nimbers (Ai^X)<=Ai

http://www.spoj.com/problems/PLAYGAME/ (3) //Check pattern

http://www.spoj.com/problems/CHAOS_CC/ (4) //VERY NICE [nimbers]

http://codeforces.com/contest/851/problem/E (5) //Very nice [nimbers] [bitset]

http://www.spoj.com/problems/CHGROOM/ (4) //+Factorisation [NICE & Easy]: Win unless 2 prime factors

Геометрия

12173 UVA 3

12194 UVA 4

11894 UVA 3

11769 UVA 7

11665 UVA 5

11509 UVA 4

11355 UVA 5

11265 UVA 6 //Nice one | polygon — cut/pt-check/area

11123 UVA 4 //Counting trapezoids

11177 UVA 6 //BS+Polygon/Circle intersection

11186 UVA 3

11008 UVA 5 //with DP → #intersected triangles

11012 UVA 5 //Nejvzdálenější body (Manhatton 3D)

11072 UVA 4 //Body v poly gonu

http://codeforces.com/problemset/problem/682/E 6 (biggest triangle)

http://codeforces.com/contest/672/problem/C 4 //easy — just think it up

http://codeforces.com/contest/667/problem/A 2 //vzorecky

http://codeforces.com/contest/793/problem/C 5 //EASY but beware of epsilons (NICE)

http://codeforces.com/contest/794/problem/B 2 //Can be done with BS

http://codeforces.com/contest/814/problem/D 5 //+DP on trees (NICE — but low geom.)

10750 UVA 3 //Closest points — try all pairs

http://codeforces.com/contest/820/problem/B 3 //Polygon angle find!

13213 UVA 5 //VERY NICE — Voronoi diagram (low constraints so not actually needed)

13215 UVA 3 //EASY — Sum areas and find side lengths

http://www.spoj.com/problems/IITKWPCC/ (5) //VERY VERY NICE — Nqrt(N)log(N)

http://www.spoj.com/problems/NNS/ (5) Closest points query [fake geometry] {__128}

http://codeforces.com/contest/849/problem/B (3) //X-Product — side

http://www.spoj.com/problems/AMR12C/ (5) //Point closest to all other points (with speed)

Графы

http://codeforces.com/contest/27/problem/D (5)

11387 (UVA) 4

http://www.spoj.com/problems/VFRIEND2/ (5) //Graph possible check

Жадность

http://codeforces.com/contest/729/problem/D 3

http://codeforces.com/contest/729/problem/E 4

http://codeforces.com/contest/725/problem/D 4

http://codeforces.com/contest/725/problem/F 9

http://codeforces.com/contest/732/problem/E 5

http://codeforces.com/contest/727/problem/F 6

http://codeforces.com/contest/724/problem/D 5

http://codeforces.com/contest/723/problem/C 4

http://codeforces.com/contest/719/problem/B 2

http://codeforces.com/contest/712/problem/C 3

13152 UVA (4)

http://codeforces.com/contest/746/problem/E 5

http://codeforces.com/contest/746/problem/D 3

http://codeforces.com/contest/749/problem/C 3

11737 UVA (3)

11786 UVA (4)

11630 UVA (5)

11563 UVA (4)

11491 UVA (4)

11330 UVA (3)

11089 UVA (2)

http://www.spoj.com/problems/SQRMINSUM/ 3 //solve-able in O(N+M)-arrayqueue

http://www.spoj.com/problems/MSCHED/ 3 //sweep from back

http://www.spoj.com/status/ns=18780683 4 //all perm + A<B<C works

http://www.spoj.com/problems/NINJA7/ (3) //sort by diff

http://www.spoj.com/problems/NINJA2/ (4) //try all possib. (26)

http://codeforces.com/contest/767/problem/E (6)

http://codeforces.com/contest/637/problem/B (3) //NICE pro prvaky

http://codeforces.com/contest/777/problem/B (3) // -||-

http://codeforces.com/contest/777/problem/D (3) //just go from end

http://codeforces.com/contest/779/problem/C (3) //NICE pro prváky

http://www.spoj.com/problems/SPCU/ (2) //Easy — zamysleni (max int = index)

http://www.spoj.com/problems/LOPOV/ (4) //sort + queue (or just queue) NICE

http://codeforces.com/contest/792/problem/E (5) //T%S<=T/S + check proper

http://codeforces.com/contest/807/problem/E (5) //NICE — put asice P2 / rest — greedy from small

http://codeforces.com/contest/799/problem/E (5) //Many queues — but NICE

http://codeforces.com/contest/808/problem/C (3) //EASY

http://codeforces.com/contest/802/problem/B (4) //Priority by "next"

10850 UVA (4) //Queue a brute-force

http://codeforces.com/contest/813/problem/A (1) //Zahrivacka pro prvaky

10716 UVA (4) //NICE — always find closest pair

http://codeforces.com/contest/816/problem/C (3) //NICE — greater<lesser side

http://codeforces.com/contest/820/problem/D (5) //VERY NICE — O(N) -~- 5 events per number

http://codeforces.com/contest/818/problem/B (2) //Zahrivacka pro prvaky

http://codeforces.com/contest/822/problem/C (4) //Almost classical Sort+Queue

http://codeforces.com/contest/825/problem/C (2) //Nice & Easy

http://codeforces.com/contest/825/problem/D (3) //Update by modulo

http://codeforces.com/contest/835/problem/B (2) // Zahhrivacka pro prvaky

http://codeforces.com/contest/839/problem/B (3) //Nasty iffs — yet nice excersize

http://www.spoj.com/problems/PCPC12I/ (4) //Swipe MINIMUM from left/right [10^6-A[i] trick]

http://www.spoj.com/problems/AMR12I/ (3) //NICE a) MAX_SEG>=K b) (SEG_SIZE-1)/K+1

http://www.spoj.com/problems/BUSYMAN/ (2) //NICE&EASY — Sort + keep minimum

Хэши

12012 UVA 4

http://codeforces.com/contest/727/problem/E 7

http://codeforces.com/contest/718/problem/D 8

11855 UVA 4

http://codeforces.com/contest/752/problem/D 5

http://codeforces.com/contest/825/problem/F 5 //String + Periods

http://codeforces.com/contest/835/problem/D 4 //Palindromes

Шахматы

11852 UVA (6)

http://www.spoj.com/problems/KLUG1/ (2) //Jumps of horse

Реализация

http://codeforces.com/contest/719/problem/C 3

http://codeforces.com/contest/747/problem/E 4

http://codeforces.com/contest/754/problem/C 5

11482 UVA (4)

11291 UVA (3)

11070 UVA (5) //evaluation of expression

11074 UVA (2)

http://codeforces.com/contest/678/problem/B 2 //calendar days

http://codeforces.com/contest/643/problem/A 3 //easy — just simulate

http://codeforces.com/contest/770/problem/D 5 //easy — but pain — draw

http://codeforces.com/contest/789/problem/B 3 //simulate (mby twice)

13171 UVA (1)

10800 UVA (3)

http://codeforces.com/contest/828/problem/B 2 //EASY & NICE — just analysis

http://codeforces.com/contest/825/problem/B 2 //EASY & NICE — Piskvorky — pro prvaky

http://codeforces.com/contest/837/problem/B 2 //Just implementation

http://codeforces.com/contest/837/problem/C 2 //Some nasty iffs

http://codeforces.com/contest/845/problem/B 2 //Easy pro prvaky

http://codeforces.com/contest/845/problem/D 3 //Iffs — folow the rules

http://www.spoj.com/problems/UNIHW/ 4 //NICE (but many iffs)

Формула включений-исключений

http://www.spoj.com/problems/KPRIMESB/ (4)

http://www.spoj.com/problems/IITKWPCH/ (4) //NICE — on bits

http://www.spoj.com/problems/SUBSET/ (5) //VERY NICE — 3^10 (^2 but not exactly) (+ sorting)

Интерактивные задачи

http://codeforces.com/contest/727/problem/C (2)

http://codeforces.com/contest/810/problem/D (4) //BS * 3 (same)

http://codeforces.com/contest/811/problem/D (4) //BFS — easy .. some ifs

http://codeforces.com/contest/835/problem/E (4) //NICE! Bitsets + Detect + XOR

http://codeforces.com/contest/844/problem/D (5) //NICE! Randomized algo

Задача Иосифа Флавия

11351 UVA (2)

http://www.spoj.com/problems/CLSLDR/ (4) //Muchas queries — go DP

Алгоритм Кнута — Морриса — Пратта

http://www.spoj.com/problems/NAJPF/ (4) //classical kmp — all patterns

http://codeforces.com/contest/808/problem/G (6) //with DP -harder

Задача LCA (наименьший общий предок)

http://codeforces.com/contest/733/problem/F 7

11354 UVA (4)

http://www.spoj.com/problems/POLICEMEN/ (3) //simple + small graph

http://www.spoj.com/problems/QTREE2/ (5) //very easy if bin. understrood

http://codeforces.com/contest/828/problem/F 7 // Differently MST / Outside

http://codeforces.com/contest/832/problem/D (5) //Classical + Depth /OR/ HLD +ST

http://www.spoj.com/problems/DRTREE/ (5) //NICE [finding ancestor + depths]

http://codeforces.com/problemset/problem/838/B (6) //VERY NICE [HLD + ET + ST]

http://www.spoj.com/problems/NTICKETS/ (4) //Maximum on path

http://www.spoj.com/problems/GRASSPLA/ (5) //HLD

Наибольшая общая подпоследовательность

10949 UVA (6) — Hunt or Bit

http://www.spoj.com/problems/MC/ (3) //Classical

http://www.spoj.com/status/ns=20097091 (4) //Permutation

http://www.spoj.com/problems/LCS0/ (7) //Bit

Задача поиска наибольшей увеличивающейся подпоследовательности

http://www.spoj.com/problems/ALTSEQ/ 3 //solvable by FW in Nlog(N)

http://www.spoj.com/problems/VISIBLEBOX/ (4) //with multiset

http://www.spoj.com/problems/DOSA/ (5)

http://www.spoj.com/problems/CODERE3/ 3 //Low bounds LIS/LDS

http://www.spoj.com/problems/BRDGHRD/ 4 //lis (nondecreasing)

Паросочетание

http://codeforces.com/contest/727/problem/D 4

11985 UVA (5)

http://www.spoj.com/problems/AMR12A/ (5) //VERY NICE goophers + bonus

http://www.spoj.com/problems/NITT4/ (4) //VERY NICE [Chessboard matching]

Матрицы

12045 UVA (4)

Экспонента матрицы

11551 UVA (4)

11486 UVA (5)

10743 UVA (5) //A001169 [easy multi / hard to come with recurence]

http://codeforces.com/contest/821/problem/E (6) //Not trivial to come-up with matrix

http://www.spoj.com/problems/DCEPCA06/ (4) //NICE — 10x10 matrix

http://www.spoj.com/problems/GSWORDS/ (3) //NICE&EASY — 3-states "OO,OX,XO"

Поток минимальной стоимости

11613 UVA (6)

http://codeforces.com/contest/802/problem/C (8) //Nice but hard to see + negative

http://codeforces.com/contest/802/problem/N (5) //Easy but faster MCMF needed

http://codeforces.com/contest/818/problem/G (6) //NICE + MUCH Faster MCMF

http://www.spoj.com/problems/BNMT/ (7) //VERY NICE (some optimalisations needed + weird data set)

Поиск медианы

http://codeforces.com/contest/713/problem/C 7

http://www.spoj.com/problems/RMID2/ 4

http://www.spoj.com/problems/RMID/ 3 (as above just not so dynamic)

http://www.spoj.com/problems/EC_ESTA/ 4 //classical dynamic median

http://www.spoj.com/problems/DCEPCA09/ (6) //VERY NICE [MO +++ MEDIAN, MEAN, FREQ]

Встреча в середине (Meet in the middle)

11851 UVA (5)

11465 UVA (5)

13207 UVA (4) //Straight-forward MIM

http://www.spoj.com/problems/COLOR_CC/ (4) //VERY NICE — div by partity (take lesser) → 8^6

Алгоритм МО

http://www.spoj.com/problems/COT/ (7) //ON TREE [but very tight TLE]

http://www.spoj.com/problems/GOT/ (5) //ON TREE

http://www.spoj.com/problems/CPAIR2/ (4) //MO + Fenwick [VERY NICE]

Магический квадрат

12192 UVA 5

http://codeforces.com/contest/729/problem/B 2

http://codeforces.com/contest/710/problem/C 4

11871 UVA 6

11617 UVA (3)

11573 UVA (4)

11499 UVA (5)

11230 UVA (4)

Теория чисел

http://codeforces.com/contest/731/problem/F 4

12031 UVA (8)

http://codeforces.com/contest/722/problem/F (8)

http://codeforces.com/contest/716/problem/C 4

http://codeforces.com/contest/711/problem/E (8)

http://codeforces.com/contest/710/problem/D (6)

13154 (UVA) 7

13166 (UVA) 5

11962 (UVA) 2

11718 UVA 3

11510 UVA (5)

11538 UVA (3) //good one — just math

11556 UVA (1)

http://codeforces.com/contest/757/problem/E (8)

http://codeforces.com/contest/758/problem/F (7)

11481 UVA (4)

11237 UVA (4) //Nice — seems like knapsbag but it it not

11155 UVA (4) //Almost as previous problem

11038 UVA (3) //counting digits on interval

http://codeforces.com/contest/763/problem/C (7)

11087 UVA (4) //Sums of two numbers divisible with <=500 (10^5)

http://codeforces.com/contest/678/problem/C 2 //LCM

http://codeforces.com/problemset/problem/665/F (8) //p^3 | p*q

http://www.spoj.com/problems/LCMSUM/ //Vzorec v knihovničce

http://www.spoj.com/problems/FRNDZND/ (2) // (size 1 == 1, else 0)

http://www.spoj.com/problems/EXPOR/ //bit-by-bit (+ formula)

http://www.spoj.com/problems/FACTDIV/ (5) //dyn-update of ans/factors GOOD

http://www.spoj.com/problems/PAIRDIV/ (6) //cyka möbius -_-

http://www.spoj.com/problems/FCDC/ (4) //keep factorized factorial

http://www.spoj.com/problems/NTHPRIME/ (7) // BS + NumPrime GOOD!!

http://www.spoj.com/problems/DIVFACT3/ (7) // Sieve 10^8 + sqrt search

http://www.spoj.com/problems/DIVFACT4/ (8) // Prime count

http://codeforces.com/contest/776/problem/C (4) //segments div. by number

http://codeforces.com/contest/776/problem/E (6) //vypsat cisla: f(N)=Phi(N),g(N)=N

http://www.spoj.com/problems/PHT/ (2) //easy BS (NN+2N) mby math?

http://www.spoj.com/problems/GCDEX/ (7) //OEIS A006579 — enough [well imp]

http://www.spoj.com/problems/APS/ (3) //just sieve + generate

http://www.spoj.com/problems/WPC5I/ (3)//fc: C[a]!=C[b]:F[a]^max(C[a],C[b])

http://www.spoj.com/problems/SPEC_SET/ N→N/k→N/k/k

http://www.spoj.com/problems/DCEPC11B/ (5) //Wilson't theorem!

http://www.spoj.com/problems/FACTMULN/ (5) //each f[i]/c[i] separately

http://www.spoj.com/problems/SPCM/ (4) //just factorisation + prime check (10^12)

http://www.spoj.com/problems/TWOGAME/ (5) //gcd == Power of 3 => YES

http://www.spoj.com/problems/MKEQUAL/ (2) //Chceck if sum is divisible by N

http://www.spoj.com/problems/TIPTOP/ (3) //sqrt(N)==N? NICE!!

http://www.spoj.com/problems/PSYCHON/ (4) // fast factorisation

http://www.spoj.com/problems/ENIGMATH/ (1) // swap and div by gcd

http://www.spoj.com/problems/SNGPG/ (3) // prime gen + check

http://codeforces.com/contest/795/problem/A (2) //brute-force

http://codeforces.com/contest/801/problem/E (6) //NICE! — Clique-DAG + inversion

http://codeforces.com/contest/798/problem/C (4) //GCD == at the beginning OR 2

http://codeforces.com/contest/803/problem/C (3) //Only "low" K and just divisors

10830 (4) //simple add 2→ sqrt(N) + their mirrors

http://codeforces.com/contest/817/problem/A (2) //check division + parity

13209 UVA (3) //Simple simulation of division (+states rememberance)

http://codeforces.com/contest/834/problem/C (4) //Has cube-root + both num divisible by cuberoot

http://codeforces.com/contest/837/problem/E (5) //Factorisation + GCD attributes

http://www.spoj.com/problems/SUMMATION/ (3) //Number contribution: 2^(N-1)

http://www.spoj.com/problems/SECTORS/ (4) //Odd len OR sum of odd indices == sum of even

http://www.spoj.com/problems/IITKWPCM/ (6) //VERY NICE — Gauss's generalisation of Wilsons Theorem

http://www.spoj.com/problems/UCV2013A/ (4) //N*(N^L-1)/(N-1)

http://www.spoj.com/problems/KIMO1/ (4) //NICE — Adding/Subing by modulus

http://www.spoj.com/problems/AFS2/ (4) //Sum of divisort (sqrt(N)) — (+128int)

http://www.spoj.com/problems/FUNNUMS/ (4) //Permutations (get ith + guess ith)

http://www.spoj.com/problems/MAY99_3/ (3) //GCD

http://www.spoj.com/problems/PUCMM334/ (3) //Classical hats problem

http://www.spoj.com/problems/LCPC11B/ (4) //Factorize + count all subsets

http://www.spoj.com/problems/THREENUMBERS/ (2) //EASY & NICE [lcm]

http://www.spoj.com/problems/GAMES/ (2) //EASY&NICE — Go discrete (by 10^k) → 10^k/GCD

http://www.spoj.com/problems/SUBSHARD/ (4) //dig10^sufix(choose sufix)*^Prefix [VERY NICE]

http://www.spoj.com/problems/INVDIV/ (6) //Sum of divisors function + factorisation [NICE]

http://www.spoj.com/problems/JNEXT/ (2) //EASY — Zahřívačka pro prváky

Последовательности OEIS

12004 UVA 2

11273 UVA 5 //https://oeis.org/A001088

11077 UVA 3 //https://oeis.org/A094638

http://www.spoj.com/problems/VECTAR5/ 3 //https://oeis.org/A038721

http://www.spoj.com/problems/ESYRCRTN/ 2 //generate and see

http://www.spoj.com/problems/IITWPC4B/ 3 //http://oeis.org/A005044

http://www.spoj.com/problems/POLCONST/ (4) //A003401+Fermat Number (Prime)

http://www.spoj.com/problems/CUTCAKE/ (3) // pattern [1 22 333 4444 55555]

10872 UVA 3 //Alcuin's Sequence

http://www.spoj.com/problems/LOVINGPW/ (3) //A000788

http://www.spoj.com/problems/CBANK/ (3) //A000292 Tetrahedral numbers

http://www.spoj.com/problems/GUMATH2/ (4) //A000240 Modulo by MOD*2

http://www.spoj.com/problems/MATHII/ (4) //A006218 (Two formulas => sqrt(N))

Оффлайн вычисления

11266 UVA (6) //slightly knapsack || moc hezka

http://codeforces.com/contest/761/problem/F (7)

http://www.spoj.com/problems/UPDATEIT/ (2) //basic method

13189 UVA (4) //simulation + sort queries

Палиндромы

http://www.spoj.com/problems/MSUBSTR/ (4) //Simple manacher (or other)

Прошедние контесты

1. Big Integer: https://a2oj.com/standings?ID=29173

2. Sieve: https://a2oj.com/standings?ID=29311

3. Factorisation: https://a2oj.com/standings?ID=29497

4. Power: https://a2oj.com/standings?ID=29722

5. Inversion: http://pastebin.com/Fk1PBMQ2

6. Matrix Exponentiation: https://a2oj.com/contest?ID=29975

7. Primality Testing: https://a2oj.com/contest?ID=30152

8. XOR TRIE: http://pastebin.com/w9Xfwf0h

9. Point in Polygon: https://a2oj.com/contest?ID=30414

10)Bridges & Articulations: https://a2oj.com/contest?ID=31087

11)Dijkstra: https://a2oj.com/contest?ID=31537

12)Belman-Ford: https://a2oj.com/contest?ID=31786

13)FW: https://a2oj.com/contest?ID=31812

14)Kruskal: https://a2oj.com/contest?ID=32579

15)LCA: https://a2oj.com/contest?ID=32584

16)Fenwick: https://a2oj.com/edit?ID=32669

17)DFS: https://a2oj.com/contest?ID=32968

18)Segment Tree: https://a2oj.com/edit?ID=33052

Сопоставление с образцом

11019 UVA (5)

Перестановки

http://codeforces.com/contest/844/problem/C 3 //NICE Permutations in array

Персистентные деревья отрезков

http://codeforces.com/contest/813/problem/E (6) //Easy but hard data structure

Ро-алгоритм Полларда

http://www.spoj.com/problems/PUCMMT02/ (7) //wrong bounds- but ll OK

Степень

11029 UVA (3)

Препроцессинг

http://codeforces.com/contest/777/problem/C (4) //NICE

http://codeforces.com/contest/818/problem/C (4) //Prefix Sum

http://codeforces.com/contest/834/problem/B (2) //26 queries — NICE rozehrivacka pro prvaky

http://www.spoj.com/problems/RANGESUM/ (4) //NICE: Offline (delta) + Prefix Sum

http://www.spoj.com/problems/RANDG/ (3) //NICE [but too low bounds] [PrefixSum] [Try all indexes]

http://www.spoj.com/problems/HARSHAD/ (3) //Sieve + simple function

http://www.spoj.com/problems/PUCMM210/ (3) //Number theory (thinking not necessary)

Проверка на простоту

http://www.spoj.com/problems/ABA12A/ (3)

10871 UVA (3) //Easy — fermat not necessary

http://www.spoj.com/problems/POP1/ (4) //Fast primality testing (or somehow)

http://www.spoj.com/problems/POP2/ (5) //NICE — same as above (yet with ll)

http://www.spoj.com/problems/POP3/ (6) //same as above (yet with big)

Очередь с приоритетами

13190 UVA (2) //just priority queue

Вероятность

11762 UVA (5)

11427 UVA (5)

11348 UVA (2)

http://codeforces.com/contest/768/problem/D (4) //With DP

http://www.spoj.com/problems/IITWPC4J/ (4) //with DP

10828 UVA (5) //Nice problem but bad statemend: Expected value of visits MC

10777 UVA (4) //NICE — yet solvable with DP

http://codeforces.com/contest/839/problem/C (3) //NICE & Easy => Tree

http://www.spoj.com/problems/ZCR/ (3) //Easy (+DP)

http://www.spoj.com/problems/IITKWPCN/ (2) //Easy — Odd/Eve (black balls)

http://codeforces.com/contest/846/problem/F (5) // Expected number of unique elements

Рекурсия

http://www.spoj.com/problems/GOC11A/ 4

13170 UVA (7) //heavy implementation — but NICE!

10854 UVA (3) //if/else

Задача RMQ (минимум на отрезке)

http://codeforces.com/contest/713/problem/D 6

http://codeforces.com/contest/675/problem/E 5

http://www.spoj.com/problems/POSTERIN/ 5 //VERY NICE — Delete all minimas

http://www.spoj.com/problems/RPLN/ (3) //RMQ only

http://www.spoj.com/problems/CITY2/ (4) //RMQ + MAP [NICE][VAGUE STATEMENT]

Структура данных rope

http://www.spoj.com/problems/AROPE/ 4

http://www.spoj.com/problems/AROPE2/ 5 //same as above (+time)

Компоненты сильной связности

http://www.spoj.com/problems/TFRIENDS/ (4) //just scc size

Дерево отрезков

http://codeforces.com/contest/739/problem/C (8)

http://codeforces.com/contest/718/problem/C (8)

http://codeforces.com/contest/750/problem/E (7)

http://codeforces.com/contest/759/problem/C (7)

11165 UVA (5)

http://codeforces.com/contest/763/problem/E (8) //VERY NICE — [non-trivial]

http://www.spoj.com/problems/BGSHOOT/ (5) //normalize — then easy

http://www.spoj.com/problems/KGSS/ (4)

http://codeforces.com/contest/765/problem/F (7) //VERY NICE — CASCADE

http://www.spoj.com/problems/GSS1/ (5) //Idea — then easy

http://www.spoj.com/problems/KQUERYO/ (5) //Seg-tree of vectors

http://codeforces.com/contest/633/problem/G (8) //EulerTree+Seg+Bitset

http://www.spoj.com/problems/NAJ0001/ (7) //10^8 int — memory (and worked)

http://www.spoj.com/problems/PRMQUER/ (5) //2 segment trees + sieve

http://www.spoj.com/problems/EC_DIVS/ (5) //dunno if intended

http://www.spoj.com/problems/DCEPC11I/ (5) //NICE — 1,2,3,4,5,.. inc

http://www.spoj.com/problems/QUE2/ (4) //kth number

http://codeforces.com/contest/785/problem/E (6) //Seg+Treap [and faster]

http://codeforces.com/contest/786/problem/B (6) //+Dijkstra

13183 UVA (6) //Merge-Sort-Tree [dunno]

http://codeforces.com/contest/803/problem/G (5) //VERY NICE!! — ST 10^9 + ST/RMQ 10^5

http://codeforces.com/contest/794/problem/F (7) //Digit by digit! (N*log(N)*100 )

http://codeforces.com/contest/811/problem/E (6) //VERY NICE — DSU (easier Timofey + animals)

http://codeforces.com/contest/817/problem/F (7) //10^18 + MEX ~~ NICE yet problematic

http://codeforces.com/contest/816/problem/B (3) //Or offline trick makes it easier

http://codeforces.com/contest/834/problem/D (5) //+Dynamic Programming | NICE

http://www.spoj.com/problems/SBO/ (5) //preLast→ last (-1), last→ now (+1) — VERY NICE

http://www.spoj.com/problems/GOODE/ (5) //NICE: Inversion + L-Mex

http://www.spoj.com/problems/CNTPRIME/ (3) //ST+Sieve (short range)

http://www.spoj.com/problems/SEGSQRSS/ (4) //NICE {weak data} ~~ SQRT works too

Последовательности

11885 UVA 7 //Previous problem requested for statement

11522 UVA 3 //Trick — low numbers only :P

Решето

11610 UVA (5)

11353 UVA (3)

http://www.spoj.com/problems/TDPRIMES/ (4)

http://www.spoj.com/problems/VECTAR8/ (3)

http://www.spoj.com/problems/NFACTOR/ (4)

http://www.spoj.com/problems/HS08PAUL/ (4) //simply generate

http://codeforces.com/contest/776/problem/B (3) //Easy — trict: PM-1/ELSE-2

http://www.spoj.com/problems/GGD/ (4) // N/lowestDiv*(lowestDiv-1)

http://codeforces.com/contest/822/problem/D (4) //DP + Lowest factor

http://www.spoj.com/problems/NGIRL/ (4) //Squares — Primes + BS == Easiest

http://www.spoj.com/problems/PTRI/ (5) //Very fast sieve necessary:/

http://www.spoj.com/problems/AFS/ (3) //Sum of divisort + DP

http://www.spoj.com/problems/BSPRIME/ (4) //Very fast sieve needed

Моделирование

12187 UVA (2)

http://codeforces.com/contest/724/problem/C 5

http://codeforces.com/contest/746/problem/C 3

11093 UVA (2)

http://codeforces.com/contest/768/problem/C (4)

http://www.spoj.com/problems/WRONG/ (5) //VERY NICE — precalculate from back, then go from front

Сортировка

12189 UVA (3)

12196 UVA (4)

http://codeforces.com/contest/731/problem/D 7

11925 UVA (4)

11979 UVA (3)

http://codeforces.com/contest/747/problem/D (4)

11890 UVA (4)

http://www.spoj.com/problems/KAOS/ (4) //pocet inverzí — GOOD problem!!!!

http://www.spoj.com/problems/KSMALL/ (5) //fast sort /or/ quick-select

http://www.spoj.com/problems/RKS/ (3) //use map

http://www.spoj.com/problems/SPCJ/ (4) //reverse + go from back

http://codeforces.com/contest/785/problem/B (2) //last-first + vice versa

http://codeforces.com/contest/798/problem/D (4) //Take 1st then take best B of every pair (sort by A)

http://codeforces.com/contest/810/problem/B (2)

http://codeforces.com/contest/810/problem/C (3) //+Math

http://codeforces.com/contest/814/problem/A (1) //Pro prváky — but nice observation

http://codeforces.com/contest/817/problem/B (3) //Frequency of TOP 3

10769 UVA (3) //Sadly N^4 passes

13208 UVA (4) //Sort + Prefix Sum

13212 UVA (3) //Number of inversions

http://codeforces.com/contest/831/problem/C (3) //NICE ~ Check all "add" against first

http://codeforces.com/contest/831/problem/D (4) //Can be solved with BS+Max-Match

http://codeforces.com/contest/841/problem/C (3) //NICE — match greatest to lowest

http://codeforces.com/contest/845/problem/C (2) //EASY — pro prvaky

http://www.spoj.com/problems/HSHW/ (4) //Test every big/low pair + big/big low/low on +/-

Остовное дерево

BLINNET SPOJ (3)

11183 UVA (4) //Directed [need to know algo!]

http://www.spoj.com/problems/ULM09/ (3) //Sum-Kruskal

http://www.spoj.com/problems/IITKWPCG/ (4) //VERY NICE [log instead of price]

Быстрый алгоритм поиска кратчайшего пути (SPFA)

11478 UVA (5)

SQRT-декомпозиция

12003 UVA 7

11990 UVA (5)

http://www.spoj.com/problems/GIVEAWAY/ (7) //SQRT + BS > [or Seg+Trie]

http://codeforces.com/contest/786/problem/C (5) //Nsqrn (bg) + sqrSegs (end)

http://codeforces.com/contest/840/problem/D (5) //NICE — Either frequent OR brute-force

Работа с STL

http://codeforces.com/contest/799/problem/B (2) //EASY — MAP

http://codeforces.com/contest/808/problem/D (3) //MAP

10887 (2) //string + map

10730 (3) //Easy with hash-map

http://codeforces.com/contest/821/problem/C (3) //STACK (vector) Nice+Easy

http://www.spoj.com/problems/SOLVEIT/ (3) //Set + lower_bound

http://www.spoj.com/problems/IITKWPCA/ (2) //Set + getline

http://codeforces.com/contest/849/problem/D (5) //Queue

http://www.spoj.com/problems/CRAN02/ (4) //Map (+Math)

http://www.spoj.com/problems/MAX_NUM/ (4) //Queue (possibly multiple ways)

http://www.spoj.com/problems/SID/ (5) //Sort + Vector (or similar) [strict TLE]

Строки

http://codeforces.com/contest/762/problem/C 5

http://www.spoj.com/problems/LCS0/ 10 //LCS

http://www.spoj.com/problems/IITWPC4H/ 2 //Frequence array

http://www.spoj.com/problems/ANAGR/ 2 //frequency + palindromes

13186 UVA (6) //Bitset + Trie ~ NICE [6-7 mby?]

http://codeforces.com/contest/798/problem/B (2) //Brute-force .. pro prváky

10745 UVA (4) //Frequency (N^2 possible if efficient!!)

http://codeforces.com/contest/822/problem/B (2) //Easy pro prvaky (slightly imple.)

http://codeforces.com/contest/828/problem/C (4) //+Sorting (process only necessary!)

http://codeforces.com/contest/832/problem/B (3) //Naive compare back+front [+freq]

http://www.spoj.com/problems/STC04/ (5) //Next + pairs O(N26) [frist look O(26^2N)]

http://www.spoj.com/problems/IITKWPCJ/ (4) //GCD or HASHING

http://www.spoj.com/problems/SUBSN/ (4) //Next (NICE — bad input):

http://www.spoj.com/problems/AMR12D/ (1) //Palindrome check //Zahrivacka pro prvaky

http://www.spoj.com/problems/BOGGLE/ (2) //EASY [MAP][STREAM]

Суффиксный массив

12191 UVA 5

SARRAY SPOJ 3

4513 LA 6

http://www.spoj.com/problems/LCS2/ 7 // must be linear (SA+LCP+MQ)

http://codeforces.com/contest/802/problem/I 7 //NICE! SA+LCP+(Segmentree/queue)

Пересечение множества отрезков (заметающая прямая)

12048 UVA (5)

Тернарный поиск

12197 UVA (4)

Топологическая сортировка

http://codeforces.com/contest/765/problem/E 5

http://codeforces.com/contest/770/problem/C 4 //reduce + toposort

http://codeforces.com/contest/825/problem/E 4 //Toposort from biggest/backward

Декартово дерево

http://codeforces.com/contest/762/problem/E 6

http://www.spoj.com/problems/COUNT1IT/ 5

http://www.spoj.com/problems/IITWPC4D/ 4 //From end — pick i-th + del i-th

http://www.spoj.com/problems/ALLIN1/ 4 //Typical treap operations

Дерево

http://codeforces.com/contest/746/problem/G 5

http://codeforces.com/contest/750/problem/F 9

http://www.spoj.com/problems/RTREE/ 3 //longest path tree — query

13175 UVA (2) //something like preorder build

http://codeforces.com/contest/796/problem/C (3) //Just counting — inc by at most 2

http://codeforces.com/contest/797/problem/D (4) //VERY NICE — sort + D&C all

http://codeforces.com/contest/805/problem/E (4) //NICE — Treewidth coloring (greedy)

http://codeforces.com/contest/828/problem/D (3) //Star construction

http://www.spoj.com/problems/TREEDEGREE/ (3) //Degree from euler tree

http://www.spoj.com/problems/UCV2013J/ (3) //Find what is leaf in Binary Tree

Префиксное дерево c битами

http://codeforces.com/contest/714/problem/C 5

http://www.spoj.com/problems/SUBXOR/ (4)

http://codeforces.com/contest/817/problem/E (5) //Classical — remember sum! NICE!

Префиксное дерево cо строками

11732 UVA (5)

11539 UVA (5)

11488 UVA (4)

http://www.spoj.com/problems/TRYCOMP/ (4)

10860 UVA (4) //DP + Trie [nice — slightly generic]

Задача коммивояжёра

10937 UVA (4) //find '!' / BFS / TSP — NICE!

10944 UVA (4)

10818 UVA (5) //Easy — but not-easy implementation: ++Dijkstra [LEX!]

http://www.spoj.com/problems/A_W_S_N/ (4) //BFS + TSP (path) — NICE

Два указателя

http://codeforces.com/contest/746/problem/F 6

11436 UVA (5)

http://codeforces.com/contest/760/problem/D 4

11386 UVA (4)

http://www.spoj.com/problems/WOWSUBSTR2/ 3

http://www.spoj.com/problems/ARRAYSUB/ 4

http://www.spoj.com/problems/CODFURY/ 3 //easy — ukazkove

http://codeforces.com/contest/769/problem/B 3 //sort + TP

http://codeforces.com/contest/814/problem/C 4 //NICE — maybe some DP +/-

http://www.spoj.com/problems/CRAN04/ 4 //NICE — (more or less) 3 pointers

http://www.spoj.com/problems/OPCPIZZA/ 3 //NICE [EASY] [AGAINS EACH OTHER]

Z-функция

http://www.spoj.com/problems/SUFEQPRE/ 4

Задача 2-SAT

11930 UVA (4)

http://codeforces.com/contest/776/problem/D (5)