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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:
1 <= nums.length <= 2 * 104-1000 <= nums[i] <= 1000-107 <= k <= 107
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