結果

問題 No.2249 GCDistance
コンテスト
ユーザー sten_san
提出日時 2023-03-17 23:16:03
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 1,509 ms / 5,000 ms
コード長 3,320 bytes
コンパイル時間 1,699 ms
コンパイル使用メモリ 195,716 KB
最終ジャッジ日時 2025-02-11 14:20:25
ジャッジサーバーID
（参考情報） 		judge1 / judge1
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ファイルパターン 結果
sample AC * 1
other AC * 10
権限があれば一括ダウンロードができます

ソースコード

diff # 

#include <bits/stdc++.h>
using namespace std;

struct iofast_t {
    iofast_t() {
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
    }
} iofast;

struct uns_t {} uns;
template <typename Element, typename Head, typename ...Args>
auto vec(Element init, Head arg, Args ...args) {
    if constexpr (sizeof...(Args) == 0) return vector(arg, init);
    else return vector(arg, vec(init, args...));
}
template <typename Element, typename Head, typename ...Args>
auto vec(uns_t, Head arg, Args ...args) {
    return vec(Element(), arg, args...);
}

template <typename Container>
auto distance(const Container &c, decltype(begin(c)) iter) {
    return distance(begin(c), iter);
}

template <typename RIter, typename Compare = less<typename iterator_traits<RIter>::value_type>>
auto isort(RIter first, RIter last, Compare comp = Compare()) {
    vector<int> i(distance(first, last));
    iota(begin(i), end(i), 0);
    sort(begin(i), end(i), [&](auto x, auto y) {
        return comp(*(first + x), *(first + y));
    });
    return i;
}

template <typename, template <typename> typename, typename = void_t<>>
struct detect : false_type {};
template <typename T, template <typename> typename Check>
struct detect<T, Check, void_t<Check<T>>> : true_type {};
template <typename T, template <typename> typename Check>
constexpr inline bool detect_v = detect<T, Check>::value;

template <typename T>
using has_member_sort = decltype(declval<T>().sort());

template <typename Container, typename Compare = less<typename Container::value_type>>
auto sorted(Container c, Compare comp = Compare()) {
    if constexpr (detect_v<Container, has_member_sort>) {
        c.sort(comp);
        return c;
    }
    else {
        sort(begin(c), end(c), comp);
        return c;
    }
}

template <typename Container, typename Compare = equal_to<typename Container::value_type>>
auto uniqued(Container c, Compare comp = Compare()) {
    c.erase(unique(begin(c), end(c), comp), end(c));
    return c;
}

template <typename T, typename Compare = less<T>>
T &chmin(T &l, T r, Compare &&f = less<T>()) { return l = min(l, r, f); }
template <typename T, typename Compare = less<T>>
T &chmax(T &l, T r, Compare &&f = less<T>()) { return l = max(l, r, f); }

template <typename F>
constexpr auto fix(F &&f) noexcept {
    return [f = std::tuple<F>(std::forward<F>(f))](auto &&...args) mutable {
        return std::get<0>(f)(fix(std::get<0>(f)), std::forward<decltype(args)>(args)...);
    };
}

int main() {
    constexpr auto lim = 10000000;

    auto pf = vec<int>(uns, lim + 1);

    iota(begin(pf), end(pf), 0);
    for (int i = 2; i <= lim / i; ++i) {
        if (pf[i] != i) {
            continue;
        }
        for (int j = i + i; j <= lim; j += i) {
            chmin(pf[j], i);
        }
    }

    auto phi = [&](int n) {
        int p = n;
        while (1 < n) {
            auto m = pf[n];
            p -= p / m;
            while (n % m == 0) {
                n /= m;
            }
        }
        return p;
    };

    auto acc = vec<int64_t>(uns, lim + 2);

    acc[0] = 0;
    for (int i = 0; i <= lim; ++i) {
        acc[i + 1] = acc[i] + phi(i);
    }

    int t; cin >> t;

    while (t--) {
        int64_t n; cin >> n;

        cout << (n * (n - 1) / 2 - acc[n + 1]) * 2 + acc[n + 1] + 1 << endl;
    }
}
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