问题描述

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.

解决方案

/**
 * 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 ) {
			if( q != null ) {
				return p.val == q.val && isSameTree( p.left, q.left ) 
                                      && isSameTree( p.right, q.right );
			} else {
				return false;
			}
		} else if( q != null ) {
			return false;
		} else {
			return true;
		}  
	}
}

Same Tree