209. 长度最小的子数组 (JAVA)

class Solution {
    public int minSubArrayLen(int s, int[] nums) {
        if(nums.length == 0) return 0;

        int start = 0;
        int end = 0;
        int minLen = Integer.MAX_VALUE;
        int sum = 0;
        for (; end < nums.length && start <= end; end++ ){
            sum += nums[end];
            if(sum < s) {
                continue;
            } 
            
            while(sum >= s){
                if(end-start+1 < minLen){
                    minLen = end-start+1;
                }
                sum -= nums[start];
                start++;
            }
            
        }
        while (start < end) {
            sum -= nums[start];
            start++;
            if(sum >= s && end-start+1 < minLen) {
                minLen = end-start+1;
            }
        }
        if(minLen < Integer.MAX_VALUE) return minLen;
        else return 0;
    }
}