解題思路:
(1)先序遍歷,遞歸判斷每個結點的值是否相等
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
bool isSameTree(TreeNode* a, TreeNode* b) {
if(a==NULL && b==NULL) return true;
if(a==NULL || b==NULL) return false;
if(a->val!=b->val) return false;
else return isSameTree(a->left,b->left)&&isSameTree(a->right,b->right);
}
};