結果

問題 No.1809 Divide NCK
コンテスト
ユーザー sten_san
提出日時 2022-01-14 21:51:56
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 23 ms / 2,000 ms
コード長 3,392 bytes
コンパイル時間 2,328 ms
コンパイル使用メモリ 207,132 KB
最終ジャッジ日時 2025-01-27 11:19:49
ジャッジサーバーID
（参考情報） 		judge3 / judge2
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ファイルパターン 結果
sample AC * 3
other AC * 39
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); }

int main() {
    constexpr auto inf = INT_MAX / 2;

    int64_t n, k, m; cin >> n >> k >> m;

    auto prime_factor = [](int64_t x) {
        auto pf = vec<tuple<int64_t, int>>(uns, 0);

        for (int i = 2; i <= x / i; ++i) {
            if (x % i != 0) {
                continue;
            }

            int c = 0;
            while (x % i == 0) {
                ++c;
                x /= i;
            }

            pf.push_back({ i, c });
        }

        if (1 < x) {
            pf.push_back({ x, 1 });
        }

        return pf;
    };

    auto fcount = [](int64_t x, int64_t p) {
        int64_t c = 0, a = p;

        while (a <= x) {
            c += x / a;

            if (a <= x / p) {
                a *= p;
                continue;
            }

            break;
        }

        return c;
    };

    auto pf = prime_factor(m);

    map<int64_t, int> comb;
    for (auto [x, _] : pf) {
        comb[x] += fcount(n, x);
        comb[x] -= fcount(k, x);
        comb[x] -= fcount(n - k, x);
    }

    int ans = inf;
    for (auto [x, y] : pf) {
        chmin(ans, comb[x] / y);
    }

    cout << ans << endl;
}
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