MIPT EJudge problems

000.c

/*
  MIPT, task #000
  "A + B"
  12.09.2011
 */

#include <stdio.h>

int main () 
{
  int a, b;

  scanf ("%d%d", &a, &b);
  printf ("%d\n", a + b);

  return 0;
}

001.c

/*
  MIPT, task #001
  "Maximum"
  12.09.2011
 */

#include <stdio.h>

#define MAX(a, b) (((a) > (b))? (a) : (b))

int main()
{
  int max, a;

  scanf ("%d", &max);
  while (1 == scanf ("%d", &a)) {
      max = MAX (max, a);
  }
  
  printf ("%d\n", max);
  return 0;
}

002.c

/*
  MIPT, task #002
  "Set Intersection"
  12.09.2011
 */

#include <stdio.h>

#define MAX_SET_SIZE 1000000

int main()
{
  char s[MAX_SET_SIZE + 1] = {0};
  int a;
  
  while (scanf ("%d", &a) && a != -1) {
    s[a] = 1;
  }

  while (scanf ("%d", &a) && a != -1) {
    if (1 == s[a]) {
      s[a] = 2;
    }
  }

  /*
    Now if s[a] == 1, then a belongs to the first set,
    and if s[a] == 2, then a belongs to the second one.
   */

  char is_intersection = 0;
  for (a = 0; a <= MAX_SET_SIZE; ++a) {
    if (2 == s[a]) {
      is_intersection = 1;
      printf ("%d ", a);
    }
  }

  if (!is_intersection) {
    puts("empty");
  }

  return 0;
}

005.scm

; MIPT, task # 005
; Random descending a tree
; 12.09.2011

(define (f tree k)
  (if (list? tree)
      (+ (f (car tree) (* k 2.0))
	 (f (cadr tree) (* k 2.0)))
      (/ tree k)))

(display (f (read) 1))

006.c

/*
  MIPT, task # 006
  "Three Squares"
  12.09.2011
*/

#include <stdio.h>
#include <math.h>

#define SQR(a) ((a) * (a))

int main ()
{
  int n, i;
  scanf ("%d", &n);

  int ans = 0;
  while (n >= 0) {
    char found = 0;
    int a, b, c;
    for (a = 0; SQR (a) <= n && !found; ++a) {
      for (b = 0; SQR (a) + SQR (b) <= n && !found; ++b) {
	c = n - SQR (a) - SQR(b);
	float sqrt_c = sqrt(c);
	if (sqrt_c == (int)(sqrt_c)) {
	  found = 1;
	  //printf ("%d + %d + %d = %d\n", SQR (a), SQR (b), SQR (c), n);
	}
      }
    }
    
    if (!found) {
      ++ans;
    }

    --n;
  }



  printf ("%d", ans);

  return 0;
}

008.c

/* MIPT, task # 008
   "Brackets"
   13.09.2011
*/

#include <stdio.h>

#define MAX_STR_LENGTH 4000

int main()
{
  char s[MAX_STR_LENGTH];

  gets (s);

  int balance = 0;
  char *cur = s;
  while (*cur) {
    if ('(' == *cur) {
      ++balance;
    } else {
      --balance;
    }
    if (balance < 0) {
      puts ("NO");
      exit (0);
    }
    ++cur;
  }

  if (!balance) {
    puts ("YES");
  } else {
    puts ("NO");
  }

  return 0;
}

009.scm

; MIPT, task # 009
; "Fibonacci numbers"
; 13.09.2011			 

(define (fib n)
  (define (fib-iter i a b)
    (if (= i n)
	a
	(fib-iter (1+ i) b (+ a b))))
  (fib-iter 0 1 1))

(display (fib (read)))

027.c

/*
  MIPT, task # 027
  "Odd number"
  13.09.2011
*/

#include <stdio.h>
#include <stdlib.h>

#define MAX_NUMBER 1000000

char odd[MAX_NUMBER + 1];

int main()
{
  int n;

  scanf ("%d", &n);
  while (n--) {
    int num;
    scanf ("%d", &num);
    odd[num] ^= 1;
  }

  int i;
  for (i = 1; i <= MAX_NUMBER; ++i) {
    if (odd[i]) {
      printf("%d\n", i);
      exit(0);
    }
  }

  return 0;
}