Coding Challenge Programming Problems

gistfile1.txt

Coding Challenges. Complete these in the language of your choice.

1. Count the number of Fibonacci numbers in given range. First few Fibonacci

numbers

are 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 141, ..

Range is 10 to 100

http://www.geeksforgeeks.org/count-fibonacci-numbers-given-range-log-time/

2. Count factorial numbers in a given range

A number F is a factorial number if there exists some integer I >= 0 such that F = I! 

(that is, F is factorial of I). Examples of factorial numbers are 1, 2, 6, 24, 120, …. 

Write a program that takes as input two long integers ‘low’ and ‘high’ where 

0 < low < high and finds count of factorial numbers in the closed interval [low, high].

Input:  low = 2,  high = 720

http://www.geeksforgeeks.org/count-factorial-numbers-in-a-given-range/

3. Find smallest values of x and y such that ax – by = 0

Given two values ‘a’ and ‘b’ that represent coefficients in “ax – by = 0″, find the 

smallest values of x and y that satisfy the equation. It may also be assumed that 

x > 0, y > 0, a > 0 and b > 0.

Input: a = 25, b = 35

http://www.geeksforgeeks.org/find-smallest-values-of-x-and-y-such-that-ax-by-0/

4. Find the smallest twins in given range 

Given a range [low..high], print the smallest twin numbers in given range (low and high 

inclusive). Two numbers are twins if they are primes and their difference is 2.

Example:

Input:  low = 10,  high = 100

Output: Smallest twins in given range: (11, 13)

Both 11 and 13 are prime numbers and difference 

between them is two, therefore twins.  And these

are the smallest twins in [10..100]

Input:  low = 50,  high = 100

http://www.geeksforgeeks.org/find-the-smallest-twin-numbers-in-given-range/

5. Find four elements a, b, c and d in an array such that a+b = c+d

Given an array of distinct integers, find if there are two pairs (a, b) and (c, d) such that

a+b = c+d, and a, b, c and d are distinct elements. If there are multiple answers, then

print any of them.

Input:   {3, 4, 7, 1, 2, 9, 8}

http://www.geeksforgeeks.org/find-four-elements-a-b-c-and-d-in-an-array-such-that-ab-cd/


1. Count numbers from 1 to n that have 4 as a digit. Given a number n, find count of all numbers from 1 to n that have 4 as a digit.
Examples
Input: n = 5
Output: 1
Output 4 has only '4' as a digit
Input: n = 50
Output: 14

Problem: Determine the ouput for input of n = 328

2. Given a number n, check if n is a Fibonacci number

Problem: Check which of the following numbers are Fibonacci
89
233
375
601
1597
4183

3. Check if a given number is "Fancy".
a fancy number is one which when rotated 180 degrees is the same. Given a number, find whether it is fancy or not. 180 degree rotations of 6, 9, 1, 0, and 8 are 9, 6, 1, 0, 8 respectively.

Example:
Input n = 96
Output true

Input n = 996
Output false

Problem: Check which of the following numbers are fancy:
6001009
68089
484

4. Count trailing zeroes in factorial of a number. Given an integer n, write a function that returns the count of trailing zeroes in n!.
Examples:
Input n = 5
Output 1
Factorial of 5 is 20 which has one trailing 0

Input n = 20
Output 4
Factorial of 20 is 2.43290200817664E18 has 4 trailing zeroes

Problem: How many trailing zeroes in factorial for input n = 100?

5. Find next greater number with same set of digits
Given a number n, find the smallest number that has same set of digits as n and is greater than n. If x is the greatest possible number with its set of digits, then print "not possible".

Examples:
Input n = "218765"
Output "251678"

Input n = "1234"
Output n = "1234"

Input "4321"
Output "Not Possible"

Problem: find next greater number with same set of digits for n = "534976"