100. Same Tree

最新推荐文章于 2024-10-14 18:27:49 发布

when_bounce

最新推荐文章于 2024-10-14 18:27:49 发布

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分类专栏： LeetCode

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本文介绍了两种检查两棵二叉树是否一致的方法：递归法和队列/栈法，并提供了详细的实现步骤。

题目描述：

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.

思路一：

递归

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

思路二：Queue/Stack

class Solution {
    public boolean isSameTree(TreeNode p, TreeNode q) {
        if (p == null && q == null)
            return true;
        else if (p == null || q == null)
            return false;
        Queue<TreeNode> q1 = new LinkedList<>();
        Queue<TreeNode> q2 = new LinkedList<>();
        q1.add(p);
        q2.add(q);
        while (!q1.isEmpty() && !q2.isEmpty())
        {
            TreeNode node1 = q1.poll();
            TreeNode node2 = q2.poll();
            if (node1.val != node2.val)
                return false;
            if (node1.left != null)
                q1.add(node1.left);
            if (node2.left != null)
                q2.add(node2.left);
            if (q1.size() != q2.size())
                return false;
            if (node1.right != null)
                q1.add(node1.right);
            if (node2.right != null)
                q2.add(node2.right);
            if (q1.size() != q2.size())
                return false;
        }
        return true;
    }
}