package LeetCode;

import java.util.*;

public class LC_111 {
    public int minDepth(TreeNode root) {
        if (root == null) return 0;
        Queue<TreeNode> que = new LinkedList<>();
        que.add(root);
        int level = 0;
        while (!que.isEmpty()) {
            int len = que.size();
            level++;
            while (len > 0) {
                TreeNode p = que.poll();
                if (p.left != null) que.add(p.left);
                if (p.right != null) que.add(p.right);
                if (p.right == null && p.left == null) return level;
                len--;
            }
        }
        return level;
    }
}