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).
public class Solution {
public int MinSubArrayLen(int s, int[] nums) {
if (nums.Length == 0)
{
return 0;
}
int start = 0;
int end = 0;
int sum = nums[0];
int min = int.MaxValue;
while (true)
{
if (sum >= s)
{
if (end - start+1 < min)
{
min = end - start+1;
}
sum -= nums[start];
start++;
}
else
{
end++;
if(end > nums.Length - 1)
{
break;
}
sum += nums[end];
}
}
return min == int.MaxValue ? 0 : min;
}
}Time Complexity: O(n)
Space Complexity: O(1)
