Number of arrays of size N whose elements are positive integers and sum is K | CPP Program to find the number of arrays of size N whose elements are positive integers and sum is K ; Return nCr ; C [ 0 ] = 1 ; nC0 is 1 ; Compute next row of pascal triangle using the previous row ; Return the number of array that can be formed of size n and sum equals to k . ; Driver Code
#include <bits/stdc++.h> NEW_LINE using namespace std ; int binomialCoeff ( int n , int k ) { int C [ k + 1 ] ; memset ( C , 0 , sizeof ( C ) ) ; for ( int i = 1 ; i <= n ; i ++ ) { for ( int j = min ( i , k ) ; j > 0 ; j -- ) C [ j ] = C [ j ] + C [ j - 1 ] ; } return C [ k ] ; } int countArray ( int N , int K ) { return binomialCoeff ( K - 1 , N - 1 ) ; } int main ( ) { int N = 2 , K = 3 ; cout << countArray ( N , K ) << endl ; return 0 ; }