Map-560. Subarray Sum Equals K

Given an array of integers and an integer k, you need to find the total number of continuous subarrays whose sum equals to k.

Example 1:

Input:nums = [1,1,1], k = 2
Output: 2

Note:

1. The length of the array is in range [1, 20,000].
2. The range of numbers in the array is [-1000, 1000] and the range of the integer k is [-1e7, 1e7].

public int subarraySum(int[] nums, int k) {
        int res = 0;
        if (nums == null || nums.length == 0) return 0;
        for (int i = 0; i < nums.length; i++) {
            int temp = k;
            for (int j = i; j >= 0; j--) {
                temp = temp - nums[j];
                if (temp == 0) res++;
            }
        }
        return res;
    }