LeetCode解题之100. Same Tree

题目描述：

100. Same Tree

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

给定两个二叉树，写一个函数来判断两个二叉树是否相等！

那就两个都（根左右）遍历一下，然后比较就好啦~~

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(p == null && q == null)
            return true;
        
        if(p == null || q == null)
            return false;
        //根节点
        if(p.val != q.val){
            return false;
        }
        //左子树
        boolean isleftsame = isSameTree(p.left,q.left);
        if(!isleftsame)
            return false;
        //右子树
        boolean isrightsame = isSameTree(p.right,q.right);
        if(!isrightsame)
            return false;
   
    return true;
        
    }
    
}