LeetCode Same Tree

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.

题意：给出两个二叉树，判断这两个树是不是相等

思路：用DFS，首先比较当前结点的值是不是相等，然后比较左子树，再比较右子树

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

第二种方法：用非递归方法，模拟递归的出栈、入栈

/*** Definition for binary tree* public class TreeNode {*     int val;*     TreeNode left;*     TreeNode right;*     TreeNode(int x) { val = x; }* }*/
public class Solution {public boolean isSameTree(TreeNode p, TreeNode q) {Queue<TreeNode> q1 = new LinkedList<TreeNode>();Queue<TreeNode> q2 = new LinkedList<TreeNode>();q1.add(p);q2.add(q);while (!q1.isEmpty() && !q2.isEmpty()) {TreeNode node1 = q1.poll();TreeNode node2 = q2.poll();if (node1 == null && node2 == null) continue;if (node1 == null || node2 == null) return false;if (node1.val != node2.val) return false;q1.add(node1.left); q2.add(node2.left);q1.add(node1.right); q2.add(node2.right);}return true;}
}

LeetCode Same Tree相关推荐

[LeetCode] Binary Tree Level Order Traversal 二叉树层次遍历(DFS | BFS)
目录: 1.Binary Tree Level Order Traversal - 二叉树层次遍历 BFS 2.Binary Tree Level Order Traversal II - 二叉树层次 ...
Leetcode | Binary Tree Maximum Path Sum
Given a binary tree, find the maximum path sum. The path may start and end at any node in the tree. ...
LeetCode N-ary Tree Level Order Traversal(bfs)
问题:给出一个n叉树,输出层次遍历思路:bfs 具体代码参考: https://github.com/wuli2496/OJ/tree/master/LeetCode/N-ary%20Tree%20 ...
LeetCode Binary Tree Right Side View(搜索)
问题:给出一个二叉树,要求输出右视图思路:因为要求输出右视图.可以考虑使用深度优先搜索或者广度优先搜索. 使用深度优先搜索时,以非递归形式,将左右子树入栈,同时使用哈希表记录深度与对应右视图的值. ...
LeetCode Binary Tree Preorder Traversal(二叉树的前序遍历)
问题:给出一个二叉树,输出前序遍历思路: 自顶向下遍历过程中,将当前结点的值加入到list中,然后处理左.右子树具体代码参考: https://github.com/wuli2496/OJ/tre ...
[LeetCode] Binary Tree Postorder Traversal 二叉树的后序遍历
Given a binary tree, return the postorder traversal of its nodes' values. For example: Given binary ...
[LeetCode] Binary Tree Postorder题解
Binary Tree Postorder Given a binary tree, return the postorder traversal of its nodes' values. For ...
[Leetcode] Binary Tree Maximum Path Sum
这是LeetCode上的一道题目,需要求二叉树中两点路径的最大和.原题是 https://oj.leetcode.com/problems/binary-tree-maximum-path-sum/ ...
[LeetCode] N-ary Tree Postorder Traversal N叉树的后序遍历
Given an n-ary tree, return the postorder traversal of its nodes' values. For example, given a 3-ary ...
[leetcode] Binary Tree Preorder Traversal
Given a binary tree, return the preorder traversal of its nodes' values. For example: Given binary t ...

LeetCode Same Tree

LeetCode Same Tree相关推荐

最新文章

热门文章