subset c++ - access heap memory after delete

// https://leetcode.com/problems/subsets/

class Solution {
public:
    vector<vector<int>> subsets(vector<int>& nums) {
        vector<int>::const_iterator it = nums.cbegin();
        vector<int>::const_iterator end = nums.cend();
        return *(subsets(it, end)); 
    }
    
private:
    vector<vector<int>>* subsets(vector<int>::const_iterator it, vector<int>::const_iterator end) {
        vector<vector<int>>* result = new vector<vector<int>>();
        // Base case
        if (it == end) {
            vector<int>* emptyVec = new vector<int>();
            result->emplace_back(*emptyVec);
            return result;
        }
        
        int curVal = *(it++);
        vector<vector<int>>* subProblemResult = subsets(it, end);
        

        auto subProblemIt = subProblemResult->begin();
        int subProblemResultSize = subProblemResult->size();
        for (int i = 0; i < subProblemResultSize; i++) {
            vector<int>* curSet = new vector<int>(*subProblemIt);
            curSet->emplace_back(curVal);
            subProblemResult->emplace_back(*curSet);
            ++subProblemIt;
        }
        return subProblemResult;
    }
};