LeetCode Same Tree

/**

 * Definition for binary tree

 * struct TreeNode {

 *     int val;

 *     TreeNode *left;

 *     TreeNode *right;

 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}

 * };

 */

class Solution {

public:

    bool isSameTree(TreeNode *p, TreeNode *q) {

        int v = ((p == NULL) << 1) + (q == NULL);

        if (v == 0x2 || v == 0x1) return false; // one NULL the other not NULL

        if (v == 0x3) return true;              // both NULL

        if (p->val != q->val) return false;     // value not match

        return isSameTree(p->left, q->left)     // check subtree

                    && isSameTree(p->right, q->right);

    }

};

继续水

第二轮：

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.

来一发Java代码：

 1 /**

 2  * Definition for binary tree

 3  * public class TreeNode {

 4  *     int val;

 5  *     TreeNode left;

 6  *     TreeNode right;

 7  *     TreeNode(int x) { val = x; }

 8  * }

 9  */

10 public class Solution {

11     public boolean isSameTree(TreeNode p, TreeNode q) {

12         return dfs(p, q);

13     }

14     

15     public boolean dfs(TreeNode root, TreeNode pair) {

16         if (root == null && pair == null) {

17             return true;

18         }

19         if (root == null || pair == null) {

20             return false;

21         }

22         if (root.val != pair.val) {

23             return false;

24         }

25         return dfs(root.left, pair.left)

26                 && dfs(root.right, pair.right);

27     }

28 }