【LeetCode】100. Same Tree 解题报告

Given two binary trees, write a function to check if they are the same or not.

Two binary trees are considered the same if they are structurally

identical and the nodes have the same value.

Example1:

Input:     1         1
/ \       / \
2   3     2   3

[1,2,3],   [1,2,3]

Output: true

Example2:

Input:     1         1
/           \
2             2

[1,2],     [1,null,2]

Output: false

Example3:

Input:     1         1
/ \       / \
2   1     1   2

[1,2,1],   [1,1,2]

Output: false

算法思路：该题的解法就是比较树的结构和内容是否一致，可以采用前序遍历，中序遍历，后序遍历。

/**
* Definition for a binary tree node.
* 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) {
if(!p&&!q)return true;
if(!p||!q)return false;
return p->val==q->val&&isSameTree(p->left,q->left)&&isSameTree(p->right,q->right);
}
};

/**
* Definition for a binary tree node.
* public class TreeNode {
*     int val;
*     TreeNode left;
*     TreeNode right;
*     TreeNode(int x) { val = x; }
* }
*/
class Solution {
public boolean isSameTree(TreeNode p, TreeNode q) {
if(p==null&&q==null)
return true;
if(p==null||q==null)
return false;
return p.val==q.val&&isSameTree(p.left,q.left)&&isSameTree(p.right,q.right);
}
}

该题为简单题