Subarray Sum Equals K

Prefix Sums, problem 3 of 7

Subarray Sum Equals K

Medium

LC #560

prefix sumhash map

Not attempted yet

Given an integer array nums and an integer k, return how many contiguous, non-empty subarrays have a sum of exactly k. Numbers may be negative.

Example 1

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

Example 2

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

[1, 2] and [3].

Example 3

Input: nums = [1, -1, 0], k = 0
Output: 3

[1, -1], [0] and [1, -1, 0].

Constraints

  • 1 ≤ len(nums) ≤ 2 · 10⁴
  • -1000 ≤ nums[i] ≤ 1000
  • -10⁷ ≤ k ≤ 10⁷

Python

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Test results

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