Find pair of a given sum in an array

 #include <iostream>

using namespace std;

void sumOfPair(int a[], int n, int sum)

{

    int left =0, right=n-1;

    while(left<right)

    {

        if(a[left]+a[right]==sum)

        {

            cout << "left="<<left << ", right=" << right;

            return;

        }

        else if(a[left]+a[right]>=sum)

            right--;

        else

            left++;

    }

}

int main() {

// your code goes here

int sortedArray[] = {1, 2, 3, 4, 6, 8, 9, 13, 17, 21, 29, 31};

sumOfPair(sortedArray, sizeof(sortedArray)/sizeof(sortedArray[0]), 27);

return 0;

}

number of paths in a matrix from top left to bottom right

#include using namespace std; 

int numPathsInMatrix(int m, int n) 

{

 if(m==1 || n==1) return 1; 

return numPathsInMatrix(m-1, n) + numPathsInMatrix(m, n-1); 

}

 int main() { 

// your code goes here cout << numPathsInMatrix(4,4); 

return 0; 

}