#codingexercise
Get count of subarrays with sum divisible by m
int GetCountDivByK(List<int> A, int k)
{
var mod = new int[k];
int sum = 0;
for (int i = 0; i < A.Count; i++)
{ 
    sum += A[i];
    mod[((sum%k)+k)%k] += 1;
}
int result = 0;
for (int i =0; i < k; i++)
    if (mod[i] > 1)
          result += (mod[i] * (mod[i]-1)) / 2;
result += mod[0];
return result;

Find the number of zeros in the binary representation of a number: 

int GetCountUnsetBits(int n) 

{ 

    int set = 0; 

    int unset = 0; 

    while (n) 

    { 

        if (n & 0x1) { 

             set++; 

        } else { 

             unset++; 

        } 

        n = n >> 1; 

    } 

    return unset; 

} 

}