题解 | #对称的二叉树#

import java.util.*;

/*
 * public class TreeNode {
 *   int val = 0;
 *   TreeNode left = null;
 *   TreeNode right = null;
 *   public TreeNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param pRoot TreeNode类 
     * @return bool布尔型
     */
    public boolean isSymmetrical (TreeNode pRoot) {
        // write code here
        return dfs(pRoot,pRoot);
    }

    private boolean dfs(TreeNode node1,TreeNode node2){
        if(node1 == null && node2 == null){
            return true;
        }

        if(node1 == null || node2 == null || node1.val != node2.val){
            return false;
        }

        return dfs(node1.left,node2.right)&&dfs(node1.right,node2.left);
    }
}