LeetCode每日一题:二叉树最小深度

问题描述

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.

问题分析

求二叉树的最小深度，一般就是到达叶子节点的最短路径，用递归返回节点即可。

代码实现

public class Solution {
    public int run(TreeNode root) {
        if(root==null)
            return 0;
        if(root.left==null&&root.right==null)
            return 1;
        if(root.left==null)
            return run(root.right)+1;
        if(root.right==null)
            return run(root.left)+1;
        return Math.min(run(root.left),run(root.right))+1;
    }
}