#LeetCode# 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.

这道题很简单，递归无脑。

/**
 * 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;
        if(root.left == null) 
            return minDepth(root.right) + 1;
            
        if(root.right == null) 
            return minDepth(root.left) + 1;
        
        return Math.min(
            minDepth(root.right), minDepth(root.left)) + 1;
        
    }
}