Maximum Size Subarray Sum Equals k

 Given an array nums and a target value k, find the maximum length of a subarray that sums to k. If there isn’t

one, return 0 instead.

Note: The sum of the entire nums array is guaranteed to fit within the 32-bit signed integer range.

Example 1: Given nums = [1, -1, 5, -2, 3], k = 3, return 4. (because the subarray [1, -1, 5, -2] sums to 3 and is the

longest)

public class MaxSizeSubArraySumK {

    public static void main(String[] args) {

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

        int k = 3;

        int max = 0;

        int sum = 0;

        Map<Integer, Integer> map = new HashMap<>();

        for(int i = 0;i<arr.length;i++){

            sum+=arr[i];

            if(sum==k){

                max = Math.max(max,i);

            }

            int diff = sum-k;

            if(map.containsKey(diff)){

                max= Math.max(max,i-map.get(diff));

            }

            if(!map.containsKey(sum)){

                map.put(sum,i);

            }

        }

        System.out.println(max);

    }

result: 8