Subarray Sum Equals K

Medium

Given an integer array nums and an integer k (passed as target), return the total number of contiguous subarrays whose sum equals k.

Example 1

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

Example 2

Input:  nums = [1,2,3], k = 3
Output: 2

Constraints

• 1 <= nums.length <= 2*10^4
• -1000 <= nums[i] <= 1000
• nums may contain negatives (sliding window will not work).