#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>

using namespace std;

int main(){
    std::vector<int> nums{ 1, 2, 3, 4, 5, 6, 7, 8, 9 };
    std::vector<int> cache (nums.size());

    // filter
    auto it = std::copy_if (nums.begin(),
                         nums.end(),
                         cache.begin(),
                         [](int n){return n % 2 == 1;});
    // shrink container to new size
    cache.resize(std::distance(cache.begin(),it));

    // map
    std::transform(cache.begin(),
                   cache.end(),
                   cache.begin(),
                   [](int n) -> int {return n * n; });

    auto result = std::accumulate(cache.begin(),
                               cache.end(),
                               0,
                               [] (int carry, int n){ return carry + n;});

    std::cout << result << std::endl;

    return 0;
}