如何在c++中遍历unordered_map of unordered_map的unordered_map

#include <iostream>
#include <unordered_map>

int main() {
    std::unordered_map<int, std::unordered_map<int, int>> mapOfMap;

    // 添加一些数据到unordered_map的unordered_map中
    mapOfMap[1][1] = 11;
    mapOfMap[1][2] = 12;
    mapOfMap[2][1] = 21;
    mapOfMap[2][2] = 22;

    // 遍历外层的unordered_map
    for (auto it = mapOfMap.begin(); it != mapOfMap.end(); ++it) {
        int outerKey = it->first;
        std::unordered_map<int, int>& innerMap = it->second;

        // 遍历内层的unordered_map
        for (auto innerIt = innerMap.begin(); innerIt != innerMap.end(); ++innerIt) {
            int innerKey = innerIt->first;
            int value = innerIt->second;

            // 打印结果
            std::cout << "Outer Key: " << outerKey << ", Inner Key: " << innerKey << ", Value: " << value << std::endl;
        }
    }

    return 0;
}