LeetCode209.长度最小的子数组

代码随想录链接

我的代码（移动窗口）：

class Solution {
public:
    int minSubArrayLen(int target, vector<int>& nums) {
        
        if(nums.size()<=2){
            int sum = 0;
            for(int i=0; i<=nums.size()-1; ++i){
                sum += nums[i];
                if(sum>= target) return i+1;
            }
            return 0;
        }

        //长度大于2
        int res = -1;
        
        int left = 0;
        int sum = 0;
        

        for(int i=0; i<nums.size(); ++i){
            sum += nums[i];

            while(sum>=target){
                int new_len = i - left + 1;     //子数组长度
                if(res==-1) res = new_len;
                else        res = min(res, new_len);

                sum -= nums[left++];
            }
        }

        return res==-1 ? 0:res;

    }
};