#include <vector>
#include <unordered_map>
#include <iostream>
 
int main() {
    using Key = std::pair<int, void*>;
    auto hash = [](const Key & k) {
        return std::hash<int>()(k.first) * 31 + std::hash<void*>()(k.second);
    };
    std::unordered_map<Key, std::vector<int>, decltype(hash)> um(8, hash);
 
    void *x, *y; x = &y; y = &x;
    um[{1, x}] = { 1, 2, 3 };
    um[{2, y}] = { 4, 5 };
 
    for (auto const &mapItem : um)
    {
        std::cout << mapItem.first.first << ", " << mapItem.first.second << ":";
        for (auto const &vecItem : mapItem.second)
            std::cout << " " << vecItem;
        std::cout << std::endl;
    }
 
	return 0;
}

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