package 数组;
/**
 * https://leetcode-cn.com/problems/minimum-size-subarray-sum/
 * @author Huangyujun
 * 
 * 注意细节：当找到满足条件的窗口时，需要固定右边界，
 * 逐渐移动左边界（缩小窗口大小），直到窗口元素和不满足要求，再改变右边界。使用while循环缩小！
 *
 */
public class _209_长度最小的子数组 {
    public int minSubArrayLen(int s, int[] nums) {
        int n = nums.length;
        if (nums == null || n == 0) return 0;
        int ans = Integer.MAX_VALUE;
        int left = 0, right = 0;
        int sum = 0;
        while (right < n) {
            sum += nums[right++];
            while (sum >= s) {
                ans = Math.min(ans, right - left);
                sum -= nums[left++];
            }
        }
        return ans == Integer.MAX_VALUE ? 0 : ans;
    }
}