有重复的给定数字组合的算法？C++

#include <iostream>
#include <unordered_map>
#include <vector>

std::vector<int> findDuplicates(const std::vector<int>& nums) {
    std::unordered_map<int, int> count;
    std::vector<int> duplicates;

    for (int num : nums) {
        count[num]++;
        if (count[num] > 1) {
            duplicates.push_back(num);
        }
    }

    return duplicates;
}

int main() {
    std::vector<int> nums = {1, 2, 3, 3, 4, 5, 5, 6};
    std::vector<int> duplicates = findDuplicates(nums);

    std::cout << "Duplicates: ";
    for (int duplicate : duplicates) {
        std::cout << duplicate << " ";
    }
    std::cout << std::endl;

    return 0;
}

Duplicates: 3 5

#include <iostream>
#include <vector>

std::vector<int> findDuplicates(const std::vector<int>& nums) {
    int n = nums.size();
    std::vector<int> bitvector(n, 0);
    std::vector<int> duplicates;

    for (int num : nums) {
        if (bitvector[num - 1] == 0) {
            bitvector[num - 1] = 1;
        } else {
            duplicates.push_back(num);
        }
    }

    return duplicates;
}

int main() {
    std::vector<int> nums = {1, 2, 3, 3, 4, 5, 5, 6};
    std::vector<int> duplicates = findDuplicates(nums);

    std::cout << "Duplicates: ";
    for (int duplicate : duplicates) {
        std::cout << duplicate << " ";
    }
    std::cout << std::endl;

    return 0;
}

Duplicates: 3 5