LeetCode 209. 长度最小的子数组

滑动窗口（双指针）

class Solution {
public:
    int minSubArrayLen(int target, vector<int>& nums) {
        int left = 0;
        int right = 0;
        int sum = 0;
        int res = INT_MAX;

        while(right < nums.size())
        {
            sum += nums[right];
            while(sum >= target)// 如果sum大于等于target，更新res，左指针前移
            {
                res = min(res, right - left + 1);
                sum -= nums[left];
                left++;
            }
            right++; // 右指针前移
        }

        return res == INT_MAX ? 0 : res;
    }
};