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。

 /**
  * Definition for a binary tree node.
  * public class TreeNode {
  *     int val;
  *     TreeNode left;
  *     TreeNode right;
  *     TreeNode(int x) { val = x; }
  * }
  */
 public class Solution {
     public int minDepth(TreeNode root) {
         if(root == null) return 0;

         int leftmin = minDepth(root.left);
         int rightmin = minDepth(root.right);

         if(leftmin==0) return rightmin + 1;
         if(rightmin==0) return leftmin + 1;
         return leftmin>rightmin?rightmin+1:leftmin+1;
     }
 }