[LeetCode] 538. Convert BST to Greater Tree

https://leetcode.com/problems/convert-bst-to-greater-tree/

Convert BST to Greater Tree - LeetCode

Convert BST to Greater Tree

 

 

전체 풀이 코드

class Solution {
public:
    TreeNode* convertBST(TreeNode* root) {
        int sum = 0;
        TreeNode* node = root;
        while (node) {
            if (node->right) {
                TreeNode* temp = run(node->right, node);   
                if (temp->left) {
                    temp->left = NULL;
                    sum += node->val;
                    node->val = sum;
                    node = node->left;
                } else {
                    temp->left = node;
                    node = node->right;
                }
            } else {
                sum += node->val;
                node->val = sum;
                node = node->left;
            }
        }
        return root;
    }
    TreeNode* run(TreeNode* node, TreeNode* pre) {
        while (node->left && node->left!=pre) node = node->left;
        return node;
    }
};