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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
function subarraySum(nums: number[], k: number): number {
let tempSum: number = 0
let ret: number = 0
const sumCount: Map<number, number> = new Map()
sumCount.set(0, 1)
for (const num of nums) {
tempSum += num
if (sumCount.has(tempSum - k)) {
ret += sumCount.get(tempSum - k)!
}
if (sumCount.has(tempSum)) {
sumCount.set(tempSum, sumCount.get(tempSum)! + 1)
} else {
sumCount.set(tempSum, 1)
}
}
return ret
}
export { subarraySum }