Same Tree

思路：递归

/** * Definition for binary tree * public class TreeNode { *     int val; *     TreeNode left; *     TreeNode right; *     TreeNode(int x) { val = x; } * } */public class Solution {    public boolean isSameTree(TreeNode p, TreeNode q) {        if(p==null&&q==null)return true;else if(p==null||q==null)return false;else{if(p.val!=q.val)return false;return isSameTree(p.left, q.left)&&isSameTree(p.right, q.right);}    }}