100. Same Tree Java Solutions

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.

Subscribe to see which companies asked this question

 1 /**
 2  * Definition for a binary tree node.
 3  * public class TreeNode {
 4  *     int val;
 5  *     TreeNode left;
 6  *     TreeNode right;
 7  *     TreeNode(int x) { val = x; }
 8  * }
 9  */
10 public class Solution {
11     public boolean isSameTree(TreeNode p, TreeNode q) {
12         if(p == null && q == null) return true;
13         if((p == null && q != null) || (p != null && q == null) ) return false;
14         return p.val==q.val && isSameTree(p.left,q.left) && isSameTree(p.right,q.right);
15     }
16     
17 }

递归重要的就是确定递归出口，第一次递归出口没有确定好，导致一直无法AC。