题目

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.

分析

写一个检查两个二叉树是否相等的函数。

二叉树相等

结构相同，对应结点的值相同

/**
 * 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) {
            if(!isSameNode(p, q))
                return false;
            if(p==null)return true;
            return isSameTree(p.left,q.left)&& isSameTree(p.right,q.right);
     }
     private boolean isSameNode(TreeNode p, TreeNode q) {
        // TODO Auto-generated method stub
         if(p==null&&q==null)
             return true;
         if(p!=null&&q!=null&&p.val==q.val)
             return true;
        return false;
    }
}

原题连接