test

package com.sgcib.bars.controller;

import java.util.HashMap;

public class Test {
	public static void main(String[] args) {

		int arr[] = { 10, 2, -2, -20, 10 };
		int sum = -10;
		int n = arr.length;
		System.out.println(findSubarraySum(arr, n, sum));
	}

	static int findSubarraySum(int arr[], int n, int sum) {
		HashMap<Integer, Integer> prevSum = new HashMap<>();
		int res = 0;
		int currsum = 0;
		for (int i = 0; i < n; i++) {
			currsum += arr[i];
			if (currsum == sum)
				res++;
			if (prevSum.containsKey(currsum - sum))
				res += prevSum.get(currsum - sum);
			Integer count = prevSum.get(currsum);
			if (count == null)
				prevSum.put(currsum, 1);
			else
				prevSum.put(currsum, count + 1);
		}
		return res;
	}
}