LeetCode--Same Tree

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：

　　判断两个二叉树是否相等。

/**

 * 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&&q==null) return true;

        if(p==null&&q!=null||p!=null&&q==null) return false;

        return isSameTree(p.left,q.left)&&isSameTree(p.right,q.right)&&(p.val==q.val);

        

        }

}

最后一句分开写的话：

/**

 * 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) {

        boolean left;

        boolean right;

        if(p==null&&q==null) return true;

        if(p==null&&q!=null||p!=null&&q==null) return false;

        if(p.val==q.val){

            left = isSameTree(p.left,q.left);

            right = isSameTree(p.right,q.right);

        }else{

            return false;

        }

        return left&&right;

        

        }

}