LeetCode: Minimum Size Subarray Sum

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.

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public class MinimumSizeSubarraySum {

public int minSubArrayLen(int s, int[] nums) {
if (nums == null || nums.length == 0) {
return 0;
}
int length = nums.length;
int start, end, crtSum, minLength;
start = end = crtSum = 0;
minLength = length + 1;

while (end < length) {

while (crtSum < s && end < length) {
crtSum += nums[end++];
}

while (crtSum >= s && start < length) {
if (end - start < minLength) {
minLength = end - start;
}
crtSum -= nums[start++];
}
}

return minLength > length ? 0 : minLength;
}
}