Leetcode - Maximum Size Subarray Sum Equals k
https://leetcode.com/problems/maximum-size-subarray-sum-equals-k/
Given an array nums and a target value k, find the maximum length of a subarray that sums to k. If there isn't one, return 0 instead.
Note:
The sum of the entire nums array is guaranteed to fit within the 32-bit signed integer range.
Example 1:
Input: nums =[1, -1, 5, -2, 3], k =3Output: 4 Explanation: The subarray[1, -1, 5, -2]sums to 3 and is the longest.
Use a hash to keep every sum for each i. And then use current_sum - previous_sum to see whether the result is equal to k.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 | func maxSubArrayLen(nums []int, k int) int { if len(nums) == 0 { return 0 } hash := map[int]int{} maxNum := 0 sum := 0 for i := 0; i < len(nums); i++ { sum += nums[i] if sum == k { maxNum = i + 1 } else { if val, ok := hash[sum - k]; ok { maxNum = max(maxNum, i - val) } } if _, ok := hash[sum]; !ok { hash[sum] = i } } return maxNum}func max(a, b int) int { if a > b { return a } return b} |
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