程式語言 - LeetCode - C++ - 450. Delete Node in a BST

參考資訊：
https://algo.monster/liteproblems/450
https://www.cnblogs.com/grandyang/p/6228252.html

題目：


解答：

/**
 * 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:
    TreeNode* deleteNode(TreeNode* root, int key) {
        if (!root) {
            return root;
        }

        if (root->val > key) {
            root->left = deleteNode(root->left, key);
        }
        else if (root->val < key) {
            root->right = deleteNode(root->right, key);
        }
        else {
            if (!root->left || !root->right) {
                root = root->left ? root->left : root->right;
            }
            else {
                struct TreeNode *cur = root->right;

                while (cur->left) {
                    cur = cur->left;
                }

                cur->left = root->left;
                root = root->right;
            }
        }

        return root;
    }
};