在不使用部分模板函数专门化的情况下限定递归`std::vector<std::vector<...>>`

template <typename T, size_t N>
struct RecursiveVector {
    using type = std::vector<typename RecursiveVector<T, N-1>::type>;
};

template <typename T>
struct RecursiveVector<T, 0> {
    using type = std::vector<T>;
};

#include <iostream>
#include <vector>

template <typename T, size_t N>
struct RecursiveVector {
    using type = std::vector<typename RecursiveVector<T, N-1>::type>;
};

template <typename T>
struct RecursiveVector<T, 0> {
    using type = std::vector<T>;
};

int main() {
    // 递归深度为3的std::vector<std::vector<std::vector<int>>>类型
    RecursiveVector<int, 3>::type vec;
    
    // 添加元素
    vec.resize(2);
    vec[0].resize(3);
    vec[1].resize(4);
    
    // 输出元素个数
    std::cout << "Size: " << vec.size() << std::endl;
    std::cout << "Inner size 1: " << vec[0].size() << std::endl;
    std::cout << "Inner size 2: " << vec[1].size() << std::endl;
    
    return 0;
}

Size: 2
Inner size 1: 3
Inner size 2: 4