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.

click to show more practice.

More practice:
If you have figured out the O(n) solution, try coding another solution of which the time complexity is O(n log n).

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

典型two-pointer题：

class Solution {
public:
int minSubArrayLen(int s, vector<int>& nums) {
int minlen = INT_MAX;
int len = nums.size();

int p = 0;
int q = 0;
int csum = 0;
while (q < len) {
csum += nums[q];
while (csum >= s) {
minlen = min(minlen, q - p + 1);
csum -=nums[p++];
}
q++;
}
return minlen == INT_MAX ? 0 : minlen;
}
};