Cinte's Leetcode Record
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450. 删除二叉搜索树中的节点

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Symbols count in article: 1.2k Reading time ≈ 1 mins.

450. 删除二叉搜索树中的节点

只改值不改节点引用

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/**
 * 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 nullptr;
        if(key > root->val)
            root->right = deleteNode(root->right, key);
        else if(key < root->val)
            root->left = deleteNode(root->left, key);
        else
        {
            if(!root->left && !root->right)
            {
                delete root;
                return nullptr;
            }
            if(root->right)
            {
                root->val = rightMin(root->right);
                root->right = deleteNode(root->right, root->val);
            }else
            {
                root->val = leftMax(root->left);
                root->left = deleteNode(root->left, root->val);
            }
        }
        return root;
    }
private:
    int rightMin(TreeNode* node)
    {
        while(node->left)
            node = node->left;
        return node->val;
    }

    int leftMax(TreeNode* node)
    {
        while(node->right)
            node = node->right;
        return node->val;
    }
};