Subarray Sum Equals K

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

Problem Details

• You are given an integer array nums and an integer k.
• You need to return the total count of continuous subarrays whose sum equals to k.
• Use a hashmap (or dictionary) to store cumulative sums and their frequencies to optimize your solution.
• Consider edge cases such as when nums is empty.

Example

Input: nums = [1, 1, 1], k = 2
Output: 2
Explanation: There are two continuous subarrays [1,1] that sum up to 2.

Starter Code

Below is some language-agnostic starter code to help you begin your solution.

Function Signature

function subarraySum(nums, k) {
    // returns the number of continuous subarrays whose sum equals k
}

Happy coding! Consider the innovative use of hashmaps as a tool that some of the greatest developers have mastered over the years.