LeetCode: same-tree

题目描述

Given two binary trees, write a function to check if they are equal or not.

Two binary trees are considered equal if they are structurally identical and the nodes have the same value.

判断两个二叉树是否相等，返回Boolean

程序实现很简单，但是注意判断的顺序，先去判断是否二叉树同时遍历完，再去与。

p == null && q == null

public class Solution {
    public boolean isSameTree(TreeNode p, TreeNode q) {
       if (p == null && q == null)
            return true;
        if(p==null||q==null){
            return false;
        }
        
        if (p.val != q.val)
            return false;
  
        return isSameTree(p.left,q.left)&&isSameTree(p.right,q.right);
    }
}