572. Subtree of Another Tree

解題思路

直覺反應是 same tree 的延伸題。

程式碼

class Solution {
public:
    bool isSame(TreeNode* root, TreeNode* subRoot)
    {
        if(root == nullptr && subRoot == nullptr)
            return true;
        if(root == nullptr || subRoot == nullptr)
            return false;
        return root->val == subRoot->val && isSame(root->left, subRoot->left)
        && isSame(root->right, subRoot->right);
    }
    bool isSubtree(TreeNode* root, TreeNode* subRoot) {
        if(root == nullptr)
            return false;
        return isSame(root, subRoot) || isSubtree(root->left, subRoot) ||
            isSubtree(root->right, subRoot);
    }
};