Leetcode 209. Minimum Size Subarray Sum
Given an array of n positive integers and a positive integer s, find the minimal length of a contiguous subarray of which the sum ≥ s. If there isn't one, return 0 instead.
Example:
Input: s = 7, nums = [2,3,1,2,4,3]
Output: 2
Explanation: the subarray [4,3]
has the minimal length under the problem constraint.
Follow up:
If you have figured out the O(n) solution, try coding another solution of which the time complexity is O(n log n).
Difficulty:Medium
Category:
Solution
Time complexity: O(n), Space complexity: O(1)
class Solution {
public:
int minSubArrayLen(int s, vector<int>& nums) {
int n = nums.size(), left = 0, right = 0, ans = INT_MAX;
int sum = 0;
for (right = 0; right < n; ++right) {
sum += nums[right];
while (sum >= s) {
ans = min(ans, right - left + 1);
sum -= nums[left++];
}
}
return ans == INT_MAX ? 0 : ans;
}
};