LeetCode111-20.8.21-二叉树的最小深度

链接：LeetCode111
过程：略
思路：dfs,看题解觉得bfs较好
代码：

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    public int minDepth(TreeNode root) {
        if(root==null)return 0;
        if(root.left==null&&root.right==null)return 1;
        if(root.left==null){
            return minDepth(root.right)+1;
        }
        if(root.right==null){
            return minDepth(root.left)+1;
        }
        return Math.min(minDepth(root.left),minDepth(root.right))+1;

    }
}