Posted on

Description

Submission

/**
* 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 {
int ret;
public:
int countUnivalSubtrees(TreeNode* root) {
if(!root) return 0;
return countUnivalSubtrees(root->left) + countUnivalSubtrees(root->right) + isUnivalSubtree(root, root->val);
}
// ret: {uni-value til now, value_of_leaf}
bool isUnivalSubtree(TreeNode* root, int val) {
if(!root) return true;
if(root->val != val) return false;
return isUnivalSubtree(root->left, val) && isUnivalSubtree(root->right, val);
}
};
/** * 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 { int ret; public: int countUnivalSubtrees(TreeNode* root) { if(!root) return 0; return countUnivalSubtrees(root->left) + countUnivalSubtrees(root->right) + isUnivalSubtree(root, root->val); } // ret: {uni-value til now, value_of_leaf} bool isUnivalSubtree(TreeNode* root, int val) { if(!root) return true; if(root->val != val) return false; return isUnivalSubtree(root->left, val) && isUnivalSubtree(root->right, val); } };
/**
 * 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 {
    int ret;
public:
    int countUnivalSubtrees(TreeNode* root) {
        if(!root) return 0;
        return countUnivalSubtrees(root->left) + countUnivalSubtrees(root->right) + isUnivalSubtree(root, root->val);
    }

    // ret: {uni-value til now, value_of_leaf}
    bool isUnivalSubtree(TreeNode* root, int val) {
        if(!root) return true;
        if(root->val != val) return false;
        return isUnivalSubtree(root->left, val) && isUnivalSubtree(root->right, val);
    }
};

Leave a Reply

Your email address will not be published. Required fields are marked *