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:
1 <= nums.length <= 2 * 104-1000 <= nums[i] <= 1000-107 <= k <= 107
Solution
class Solution {
/**
* @param Integer[] $nums
* @param Integer $k
* @return Integer
*/
public function subarraySum($nums, $k) {
$tempSum = 0;
$ret = 0;
$sumCount = array();
$sumCount[0] = 1;
foreach ($nums as $i) {
$tempSum += $i;
if (isset($sumCount[$tempSum - $k])) {
$ret += $sumCount[$tempSum - $k];
}
if (isset($sumCount[$tempSum])) {
$sumCount[$tempSum] = $sumCount[$tempSum] + 1;
} else {
$sumCount[$tempSum] = 1;
}
}
return $ret;
}
}