LeetCode-in-All

560. Subarray Sum Equals K

Medium

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

Example 1:

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

Output: 2

Example 2:

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

Output: 2

Constraints:

Solution

# @param {Integer[]} nums
# @param {Integer} k
# @return {Integer}
def subarray_sum(nums, k)
  temp_sum = 0
  ret = 0
  sum_count = {0 => 1}

  nums.each do |i|
    temp_sum += i
    ret += sum_count[temp_sum - k] if sum_count[temp_sum - k]
    sum_count[temp_sum] = sum_count[temp_sum].to_i + 1
  end

  ret
end