[LeetCode]Same Tree

Question

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.

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本题难度Easy。

递归

【复杂度】
时间 O(N) 空间 O(1)

【思路】
递归对比两个节点的值。

【代码】

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