結果

問題 No.1489 Repeat Cumulative Sum
ユーザー KoDKoD
提出日時 2021-04-23 21:40:50
言語 C++17
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 17 ms / 2,000 ms
コード長 7,431 bytes
コンパイル時間 2,036 ms
コンパイル使用メモリ 205,376 KB
実行使用メモリ 6,944 KB
最終ジャッジ日時 2024-07-04 07:46:24
合計ジャッジ時間 3,436 ms
ジャッジサーバーID
(参考情報)
judge5 / judge2
このコードへのチャレンジ
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 2 ms
6,816 KB
testcase_01 AC 1 ms
6,816 KB
testcase_02 AC 2 ms
6,940 KB
testcase_03 AC 15 ms
6,944 KB
testcase_04 AC 13 ms
6,940 KB
testcase_05 AC 15 ms
6,940 KB
testcase_06 AC 11 ms
6,940 KB
testcase_07 AC 8 ms
6,940 KB
testcase_08 AC 5 ms
6,944 KB
testcase_09 AC 16 ms
6,940 KB
testcase_10 AC 15 ms
6,940 KB
testcase_11 AC 10 ms
6,944 KB
testcase_12 AC 3 ms
6,940 KB
testcase_13 AC 10 ms
6,940 KB
testcase_14 AC 17 ms
6,940 KB
testcase_15 AC 16 ms
6,944 KB
testcase_16 AC 9 ms
6,940 KB
testcase_17 AC 10 ms
6,940 KB
testcase_18 AC 8 ms
6,940 KB
testcase_19 AC 6 ms
6,944 KB
testcase_20 AC 8 ms
6,944 KB
testcase_21 AC 11 ms
6,944 KB
testcase_22 AC 3 ms
6,940 KB
testcase_23 AC 5 ms
6,944 KB
testcase_24 AC 2 ms
6,944 KB
testcase_25 AC 4 ms
6,940 KB
testcase_26 AC 17 ms
6,944 KB
testcase_27 AC 10 ms
6,940 KB
testcase_28 AC 2 ms
6,944 KB
testcase_29 AC 9 ms
6,940 KB
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 i32 = std::int32_t;
using u32 = std::uint32_t;
using i64 = std::int64_t;
using u64 = std::uint64_t;
using i128 = __int128_t;
using u128 = __uint128_t;
using isize = std::ptrdiff_t;
using usize = std::size_t;

class rep {
    struct Iter {
        usize itr;
        constexpr Iter(const usize pos) noexcept : itr(pos) {}
        constexpr void operator++() noexcept { ++itr; }
        constexpr bool operator!=(const Iter& other) const noexcept {
            return itr != other.itr;
        }
        constexpr usize operator*() const noexcept { return itr; }
    };
    const Iter first, last;

  public:
    explicit constexpr rep(const usize first, const usize last) noexcept
        : first(first), last(std::max(first, last)) {}
    constexpr Iter begin() const noexcept { return first; }
    constexpr Iter end() const noexcept { return last; }
};

class revrep {
    struct Iter {
        usize itr;
        constexpr Iter(const usize pos) noexcept : itr(pos) {}
        constexpr void operator++() noexcept { --itr; }
        constexpr bool operator!=(const Iter& other) const noexcept {
            return itr != other.itr;
        }
        constexpr usize operator*() const noexcept { return itr; }
    };
    const Iter first, last;

  public:
    explicit constexpr revrep(const usize first, const usize last) noexcept
        : first(last - 1), last(std::min(first, last) - 1) {}
    constexpr Iter begin() const noexcept { return first; }
    constexpr Iter end() const noexcept { return last; }
};

template <class T> constexpr T totient(T x) {
    T ret = x;
    for (T i = 2; i * i <= x; ++i) {
        if (x % i == 0) {
            ret /= i;
            ret *= i - 1;
            while (x % i == 0) x /= i;
        }
    }
    if (x > 1) {
        ret /= x;
        ret *= x - 1;
    }
    return ret;
}

template <class T> constexpr T rem_euclid(T value, const T& mod) {
    return (value %= mod) >= 0 ? value : value + mod;
}

template <u32 MOD,
          std::enable_if_t<((u32)1 <= MOD and MOD <= ((u32)1 << 31))>* =
              nullptr>
class StaticModint {
    using Mint = StaticModint;

    static inline constexpr u32 PHI = totient(MOD);
    u32 v;

  public:
    static constexpr u32 mod() noexcept { return MOD; }

    template <class T,
              std::enable_if_t<std::is_signed_v<T> and std::is_integral_v<T>>* =
                  nullptr>
    static constexpr T normalize(const T x) noexcept {
        return rem_euclid<std::common_type_t<T, i64>>(x, MOD);
    }
    template <class T,
              std::enable_if_t<std::is_unsigned_v<T> and
                               std::is_integral_v<T>>* = nullptr>
    static constexpr T normalize(const T x) noexcept {
        return x % MOD;
    }

    constexpr StaticModint() noexcept : v(0) {}
    template <class T>
    constexpr StaticModint(const T x) noexcept : v(normalize(x)) {}
    template <class T> static constexpr Mint raw(const T x) noexcept {
        Mint ret;
        ret.v = x;
        return ret;
    }

    constexpr u32 get() const noexcept { return v; }
    constexpr Mint neg() const noexcept { return raw(v == 0 ? 0 : MOD - v); }
    constexpr Mint inv() const noexcept { return pow(PHI - 1); }
    constexpr Mint pow(u64 exp) const noexcept {
        Mint ret(1), mult(*this);
        for (; exp > 0; exp >>= 1) {
            if (exp & 1) ret *= mult;
            mult *= mult;
        }
        return ret;
    }

    constexpr Mint operator-() const noexcept { return neg(); }
    constexpr Mint operator~() const noexcept { return inv(); }

    constexpr Mint operator+(const Mint& rhs) const noexcept {
        return Mint(*this) += rhs;
    }
    constexpr Mint& operator+=(const Mint& rhs) noexcept {
        if ((v += rhs.v) >= MOD) v -= MOD;
        return *this;
    }

    constexpr Mint operator-(const Mint& rhs) const noexcept {
        return Mint(*this) -= rhs;
    }
    constexpr Mint& operator-=(const Mint& rhs) noexcept {
        if (v < rhs.v) v += MOD;
        v -= rhs.v;
        return *this;
    }

    constexpr Mint operator*(const Mint& rhs) const noexcept {
        return Mint(*this) *= rhs;
    }
    constexpr Mint& operator*=(const Mint& rhs) noexcept {
        v = (u64)v * rhs.v % MOD;
        return *this;
    }

    constexpr Mint operator/(const Mint& rhs) const noexcept {
        return Mint(*this) /= rhs;
    }
    constexpr Mint& operator/=(const Mint& rhs) noexcept {
        return *this *= rhs.inv();
    }

    constexpr bool operator==(const Mint& rhs) const noexcept {
        return v == rhs.v;
    }
    constexpr bool operator!=(const Mint& rhs) const noexcept {
        return v != rhs.v;
    }
    friend std::ostream& operator<<(std::ostream& stream, const Mint& rhs) {
        return stream << rhs.v;
    }
};

using Modint1000000007 = StaticModint<1000000007>;
using Modint998244353 = StaticModint<998244353>;

constexpr u64 ceil_log2(const u64 x) {
    u64 e = 0;
    while (((u64)1 << e) < x) ++e;
    return e;
}

template <class F> class AutoRealloc {
    using R = typename decltype(std::declval<F>()((usize)0))::value_type;
    F func;
    std::vector<R> data;

  public:
    template <class G>
    explicit AutoRealloc(G&& g) : func(std::forward<G>(g)), data() {}
    void reserve(const usize size) {
        if (data.size() < size) {
            const usize pow2 = ((usize)1 << ceil_log2(size));
            data = func(pow2);
        }
    }
    R operator[](const usize i) {
        reserve(i + 1);
        return data[i];
    }
};

template <class G> explicit AutoRealloc(G&&) -> AutoRealloc<std::decay_t<G>>;

template <class M> struct ModintUtil {
    static inline auto fact = AutoRealloc([](const usize n) {
        std::vector<M> ret(n);
        ret[0] = M(1);
        for (const usize i : rep(1, n)) {
            ret[i] = ret[i - 1] * M(i);
        }
        return ret;
    });
    static inline auto inv = AutoRealloc([](const usize n) {
        std::vector<M> ret(n);
        if (n == 1) return ret;
        ret[1] = M(1);
        for (const usize i : rep(2, n)) {
            ret[i] = -M(M::mod() / i) * ret[M::mod() % i];
        }
        return ret;
    });
    static inline auto inv_fact = AutoRealloc([](const usize n) {
        std::vector<M> ret(n);
        ret[0] = M(1);
        for (const usize i : rep(1, n)) {
            ret[i] = ret[i - 1] * inv[i];
        }
        return ret;
    });
    static M binom(const usize n, const usize k) {
        assert(k <= n);
        return fact[n] * inv_fact[n - k] * inv_fact[k];
    }
    static M factpow(const usize n, const usize k) {
        assert(k <= n);
        return fact[n] * inv_fact[n - k];
    }
    static M homo(const usize n, const usize k) {
        if (n == 0 and k == 0) return M(1);
        return binom(n + k - 1, k);
    }
};

template <class T> using Vec = std::vector<T>;

using Fp = Modint1000000007;
using Util = ModintUtil<Fp>;

void E_main() {
    usize N, M;
    std::cin >> N >> M;
    Fp ans;
    Vec<Fp> calc(N);
    calc[N - 1] = 1;
    for (const auto i : revrep(0, N - 1)) {
        calc[i] = calc[i + 1] * (N + M - 2 - i);
    }
    for (const auto i : rep(0, N - 1)) {
        u32 x;
        std::cin >> x;
        ans += calc[i] * Util::inv_fact[N - 1 - i] * x;
    }
    std::cout << ans << '\n';
}

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    E_main();
    return 0;
}
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