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.

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);
    }
}