Subarray Sum Equals K
Function Name: subarraySum
Description
Write a function 'subarraySum' that takes an array of integers (nums) and an integer (k), and returns the number of continuous subarrays whose sum equals to k.
You may assume that the array and the target integer k will have at least one element.
Note that the array can contain both positive and negative integers.
Requirements
- The function must have two parameters: an array of integers (nums) and a single integer (k).
- The function should return the count of the subarrays as an integer.
- Optimize the function for time complexity.
- Do not use any built-in libraries or functions that would trivialize the problem (like combinations generator).
- Subarrays are contiguous elements of the array.
- A subarray with zero length (empty) is not a valid subarray.
Examples
Given nums = [1, 1, 1] and k = 2, your function should return 2, since the subarrays [1, 1] and [1, 1] sum to 2.Example call: subarraySum([1, 1, 1], 2) returns 2.
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