100. 相同的树

题目

给你两棵二叉树的根节点 p 和 q ，编写一个函数来检验这两棵树是否相同。如果两个树在结构上相同，并且节点具有相同的值，则认为它们是相同的。

https://leetcode.cn/problems/same-tree/submissions/

解法

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
 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);
    }
}