. - 力扣（LeetCode）

class Solution {
public:int shortestSubarray(vector<int>& nums, int k) {int n = nums.size();vector<long> preSumArr(n + 1);for (int i = 0; i < n; i++) {preSumArr[i + 1] = preSumArr[i] + nums[i];}int res = n + 1;deque<int> qu;for (int i = 0; i <= n; i++) {long curSum = preSumArr[i];while (!qu.empty() && curSum - preSumArr[qu.front()] >= k) {res = min(res, i - qu.front());qu.pop_front();}while (!qu.empty() && preSumArr[qu.back()] >= curSum) {qu.pop_back();}qu.push_back(i);}return res < n + 1 ? res : -1;}
};