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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:
    vector<TreeNode*> ans;
    unordered_map < int, bool > mp;
    
    void getTheRoots(TreeNode* &root, vector<int>& to_delete) {
        if(root == NULL) return;
                
        getTheRoots(root->left,to_delete);
        getTheRoots(root->right,to_delete);
        
        if(mp[root->val]) {
             if(root->left!=NULL){
                 ans.push_back(root->left);
             }
             if(root->right!=NULL){
                 ans.push_back(root->right);
             }
             
             root = NULL;
        }

        return;
    }
    
    vector<TreeNode*> delNodes(TreeNode* root, vector<int>& to_delete) {
        for(int i=0;i<to_delete.size();i++) {
            mp[to_delete[i]] = true;
        }
    
        
        getTheRoots(root,to_delete);
        
        if(root){
            ans.push_back(root);
        }
        
        return ans;
    }
};