/**********************************************************

Given an unsorted array A of size N that contains only positive integers, 

find a continuous sub-array that adds to a given number S and return the left and right index(1-based indexing) of that subarray.

In case of multiple subarrays, return the subarray indexes which come first on moving from left to right.

Note:- You have to return an ArrayList consisting of two elements left and right. In case no such subarray exists return an array consisting of element -1.

​

// AMZ //

*****************************************************/

​

​

using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        int[] arr = {1,2,3,7,5};

        int targetSum = 12;

        List<int> result = subarraySum(arr,arr.Length ,targetSum);

        if (result[0] == -1) {

           Console.WriteLine("No subarray found");

        } else {

            Console.WriteLine("Subarray found from index " + result[0] + " to " + result[1]);

        }

    }

     public static List<int> subarraySum(int[] arr, int n, int s)

     {

         List<int> list = new List<int>();

         int left = 0, right = 0;

         int currentSum = 0;

         while(right < n){

            currentSum += arr[right];

             while(currentSum > s){

                currentSum -= arr[left];

                 left++;

             }

            if(currentSum == s){

                list.Add(left+1);

                list.Add(right+1);

                return list;

            }

             right++;

         }

         list.Add(-1);

         return list;

     }

}