[LeetCode] Minimum Size Subarray Sum

 

Given an array of n positive integers and a positive integer s, find the minimal length of a subarray of which the sum ≥ s. If there isn't one, return 0 instead.

For example, given the array [2,3,1,2,4,3] and s = 7,
the subarray [4,3] has the minimal length under the problem constraint.

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Credits:
Special thanks to @Freezen for adding this problem and creating all test cases.

滑动窗口。

 1 class Solution {

 2 public:

 3     int minSubArrayLen(int s, vector<int>& nums) {

 4         int sum = 0, len = nums.size(), start = 0;

 5         bool flag = false;

 6         for (int end = 0; end < nums.size(); ++end) {

 7             sum += nums[end];

 8             while (sum >= s) {

 9                 flag = true;

10                 len = min(len, end - start + 1);

11                 sum -= nums[start++];

12             }

13         }

14         return flag ? len : 0;

15     }

16 };