LeetCode OJ 111. Minimum Depth of Binary Tree

Given a binary tree, find its minimum depth.

The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.

这个题目很简单，也是用递归来解决。

 1 /**
 2  * Definition for a binary tree node.
 3  * public class TreeNode {
 4  *     int val;
 5  *     TreeNode left;
 6  *     TreeNode right;
 7  *     TreeNode(int x) { val = x; }
 8  * }
 9  */
10 public class Solution {
11     public int minDepth(TreeNode root) {
12         if(root == null) return 0;
13         
14         int leftmin = minDepth(root.left);
15         int rightmin = minDepth(root.right);
16         
17         if(leftmin==0) return rightmin + 1;
18         if(rightmin==0) return leftmin + 1;
19         return leftmin>rightmin?rightmin+1:leftmin+1;
20     }
21 }