Given two binary trees, write a function to check if they are the same or not.
Two binary trees are considered the same if they are structurally identical and the nodes have the same value.
Example 1:
Input: 1 1
/ \ / \
2 3 2 3
[1,2,3], [1,2,3]
Output: true
Example 2:
Input: 1 1
/ \
2 2
[1,2], [1,null,2]
Output: false
Example 3:
Input: 1 1
/ \ / \
2 1 1 2
[1,2,1], [1,1,2]
Output: false
难度：easy
题目：给定两二叉树，写函数检查它们是否相同。两个二叉树是否相同是由其结构和值都相同来决定。
思路：递归
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) {val = x;}
* }
*/
class Solution {
public boolean isSameTree(TreeNode p, TreeNode q) {
if (null == p && null != q || null != p && null == q) {
return false;
}
if (null == p && null == q) {
return true;
}
if (p.val != q.val) {
return false;
}
return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
}
}