Leet Code 100 Same Tree

Same Tree

Question

Total Accepted: 94258 Total
Submissions: 224120 Difficulty: Easy

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.

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11

如果两棵树都为空,那么应该是相同的.

如果两棵树一棵为空,一棵树非空,那么是不同的

如果两棵树都不为空,但是根节点的值不同,那么两棵树不同

如果两个树根节点数据相同,就递归判断它们的左子树和又子树是否都相同.

/**
* 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||!q&&p||p->val!=q->val)
return false;
return isSameTree(p->left,q->left)&&isSameTree(p->right,q->right);
}
};