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;
    }
}