Find subarray with given sum | Set 1 ( Nonnegative Numbers ) | An efficient program to print subarray with sum as given sum ; Returns true if the there is a subarray of arr [ ] with a sum equal to ' sum ' otherwise returns false . Also , prints the result ; Initialize curr_sum as value of first element and starting point as 0 ; Add elements one by one to curr_sum and if the curr_sum exceeds the sum , then remove starting element ; If curr_sum exceeds the sum , then remove the starting elements ; If curr_sum becomes equal to sum , then return true ; Add this element to curr_sum ; If we reach here , then no subarray ; Driver Code
#include <iostream> NEW_LINE using namespace std ; int subArraySum ( int arr [ ] , int n , int sum ) { int curr_sum = arr [ 0 ] , start = 0 , i ; for ( i = 1 ; i <= n ; i ++ ) { while ( curr_sum > sum && start < i - 1 ) { curr_sum = curr_sum - arr [ start ] ; start ++ ; } if ( curr_sum == sum ) { cout << " Sum ▁ found ▁ between ▁ indexes ▁ " << start << " ▁ and ▁ " << i - 1 ; return 1 ; } if ( i < n ) curr_sum = curr_sum + arr [ i ] ; } cout << " No ▁ subarray ▁ found " ; return 0 ; } int main ( ) { int arr [ ] = { 15 , 2 , 4 , 8 , 9 , 5 , 10 , 23 } ; int n = sizeof ( arr ) / sizeof ( arr [ 0 ] ) ; int sum = 23 ; subArraySum ( arr , n , sum ) ; return 0 ; }