lintcode--155. 二叉树的最小深度

描述

样例

给出一棵如下的二叉树:

1

/     \

2       3

/  \

4     5

这个二叉树的最小深度为 2

代码

/**
* Definition of TreeNode:
* public class TreeNode {
*     public int val;
*     public TreeNode left, right;
*     public TreeNode(int val) {
*         this.val = val;
*         this.left = this.right = null;
*     }
* }
*/

public class Solution {
/*
* @param root: The root of binary tree
* @return: An integer
*/
public int minDepth(TreeNode root) {
// write your code here
if(root==null){
return 0;
}
if(root.left==null){
return 1+minDepth(root.right);
}
if(root.right==null){
return 1+minDepth(root.left);
}
return Math.min(minDepth(root.left),minDepth(root.right))+1;
}
}