MinimumSizeSubarraySum.java

package array;

/**
 * Description: https://leetcode.com/problems/minimum-size-subarray-sum
 * Difficulty: Medium
 * Time complexity: O(n)
 * Space complexity: O(1)
 */
public class MinimumSizeSubarraySum {

    public int minSubArrayLen(int target, int[] nums) {
        int left = 0;
        int sum = 0;
        int min = Integer.MAX_VALUE;
        for (int right = 0; right < nums.length; right++) {
            sum += nums[right];
            while (sum >= target) {
                min = Math.min(min, right - left + 1);
                sum -= nums[left];
                left++;
            }
        }

        return min == Integer.MAX_VALUE ? 0 : min;
    }
}