# 思路

以recursive遍歷判斷tree中所有node的值是否相同

# 參考程式碼

/**
 * 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) {}
 * };
 */

static auto fast_io = []
{
	ios::sync_with_stdio(false);
	cout.tie(nullptr);
	cin.tie(nullptr);
	return 0;
}();

class Solution {
public:
    bool isSameTree(TreeNode* p, TreeNode* q)
    {
        if (!p && !q) return true;
        if ((p && !q) || (!p && q) || (p->val != q->val)) return false;
        return isSameTree(p->left, q->left) && isSameTree(p->right, q->right);
    }
};