merge sort

#include".\template\headers.hpp"

// #define MULTI_TASKCASE
using namespace abb;
using namespace output;
using namespace rit;
using namespace wit;

inline void init() {

}

constexpr int n = 1e5;

void merge_sort(A<int, n>& arr, int l = 0, int r = n) {
    if (r - l < 2) return;
    static A<int, n> tmp;
    int m = (l + r) >> 1;
    merge_sort(arr, l, m);
    merge_sort(arr, m, r);
    auto t = tmp.begin(), a = arr.begin();
    copy(a + l, a + m, t + l);
    copy(a + m, a + r, t + m);
    int i = l, lp = l, rp = m;
    while (lp < m && rp < r) {
        if (t[lp] < t[rp])
            a[i++] = t[lp++];
        else
            a[i++] = t[rp++];
    }
    while (lp < m)
        a[i++] = t[lp++];
    while (rp < r)
        a[i++] = t[rp++];
}

inline void solve() {
    static A<int, n> v;
    A<double, 20> arr;
    fstream filein("in.txt", ios::in);
    cin.rdbuf(filein.rdbuf());
    for (auto& k : arr) {
        cout << "poop" << ' ';
        for (auto& i : v)
            cin >> i;
        clock_t before = clock();
        merge_sort(v);
        clock_t after = clock();
        k = double(after - before) / CLOCKS_PER_SEC * 1000;
    }
    filein.close();
    cout << endl << flush;
    fstream fileout("out.txt", ios::out);
    cout.rdbuf(fileout.rdbuf());
    for (int i = 0; i != 20; i++)
        cout << arr[i] << endl;
    fileout.close();
}

main() {
    ios::sync_with_stdio(false);
    init();
    int t = 1;
#ifdef MULTI_TASKCASE
    cin >> t; cin.ignore();
#endif
    while (t--) solve();
    return 0;
}