798. Subarray Sum Equals K

You are analyzing a stream of daily metric deltas and need to count how many contiguous time windows sum to a target value.

Given an integer array nums and an integer k, return the total number of continuous subarrays whose sum equals k.

Examples

subarraySum([1,1,1], 2); // 2
subarraySum([1,2,3], 3); // 2