#769604 (C++17) No.1975 Zigzag Sequence

• 問題: No.1975 Zigzag Sequence
• ユーザー: Forested
• 提出日時: 2022-06-10 21:54:12
• 言語: C++17 (gcc 12.3.0 + boost 1.83.0)
• 結果: AC
• 実行時間: 63 ms / 2,000 ms
• コード長: 11,840 bytes
• コンパイル時間: 1,696 ms
• コンパイル使用メモリ: 142,456 KB
• 実行使用メモリ: 7,212 KB
• 最終ジャッジ日時: 2024-09-21 06:14:03
• 合計ジャッジ時間: 4,201 ms
• ジャッジサーバーID （参考情報）: judge2 / judge4

入力	結果	実行時間; 実行使用メモリ
testcase_00	AC	2 ms; 6,812 KB
testcase_01	AC	2 ms; 6,944 KB
testcase_02	AC	2 ms; 6,944 KB
testcase_03	AC	7 ms; 6,940 KB
testcase_04	AC	4 ms; 6,940 KB
testcase_05	AC	57 ms; 6,944 KB
testcase_06	AC	34 ms; 6,944 KB
testcase_07	AC	8 ms; 6,940 KB
testcase_08	AC	39 ms; 6,940 KB
testcase_09	AC	50 ms; 6,940 KB
testcase_10	AC	37 ms; 6,940 KB
testcase_11	AC	41 ms; 6,944 KB
testcase_12	AC	11 ms; 6,944 KB
testcase_13	AC	2 ms; 6,944 KB
testcase_14	AC	2 ms; 6,940 KB
testcase_15	AC	2 ms; 6,940 KB
testcase_16	AC	2 ms; 6,940 KB
testcase_17	AC	2 ms; 6,944 KB
testcase_18	AC	37 ms; 7,212 KB
testcase_19	AC	37 ms; 7,204 KB
testcase_20	AC	46 ms; 7,208 KB
testcase_21	AC	46 ms; 7,208 KB
testcase_22	AC	35 ms; 7,208 KB
testcase_23	AC	34 ms; 7,080 KB
testcase_24	AC	42 ms; 7,208 KB
testcase_25	AC	43 ms; 7,080 KB
testcase_26	AC	63 ms; 7,208 KB
testcase_27	AC	60 ms; 7,208 KB
testcase_28	AC	42 ms; 7,204 KB
testcase_29	AC	41 ms; 7,208 KB
testcase_30	AC	42 ms; 7,208 KB
testcase_31	AC	41 ms; 7,204 KB
testcase_32	AC	41 ms; 7,208 KB
testcase_33	AC	42 ms; 7,204 KB
testcase_34	AC	58 ms; 7,080 KB
testcase_35	AC	58 ms; 7,208 KB

ソースコード

#ifndef LOCAL
#define FAST_IO
#endif

// ===== template.hpp =====
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <cmath>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

#define OVERRIDE(a, b, c, d, ...) d
#define REP2(i, n) for (i32 i = 0; i < (i32) (n); ++i)
#define REP3(i, m, n) for (i32 i = (i32) (m); i < (i32) (n); ++i)
#define REP(...) OVERRIDE(__VA_ARGS__, REP3, REP2)(__VA_ARGS__)
#define PER(i, n) for (i32 i = (i32) (n) - 1; i >= 0; --i)
#define ALL(x) begin(x), end(x)

using namespace std;

using u32 = unsigned int;
using u64 = unsigned long long;
using u128 = __uint128_t;
using i32 = signed int;
using i64 = signed long long;
using i128 = __int128_t;
using f64 = double;
using f80 = long double;

template <typename T>
using Vec = vector<T>;

template <typename T>
bool chmin(T &x, const T &y) {
    if (x > y) {
        x = y;
        return true;
    }
    return false;
}
template <typename T>
bool chmax(T &x, const T &y) {
    if (x < y) {
        x = y;
        return true;
    }
    return false;
}

istream &operator>>(istream &is, i128 &x) {
    i64 v;
    is >> v;
    x = v;
    return is;
}
ostream &operator<<(ostream &os, i128 x) {
    os << (i64) x;
    return os;
}
istream &operator>>(istream &is, u128 &x) {
    u64 v;
    is >> v;
    x = v;
    return is;
}
ostream &operator<<(ostream &os, u128 x) {
    os << (u64) x;
    return os;
}

template <typename F, typename Comp = less<>>
Vec<i32> sort_index(i32 n, F f, Comp comp = Comp()) {
    Vec<i32> idx(n);
    iota(ALL(idx), 0);
    sort(ALL(idx), [&](i32 i, i32 j) -> bool {
        return comp(f(i), f(j));
    });
    return idx;
}

[[maybe_unused]] constexpr i32 INF = 1000000100;
[[maybe_unused]] constexpr i64 INF64 = 3000000000000000100;

#ifdef FAST_IO
__attribute__((constructor)) void fast_io() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(10);
}
#endif
// ===== template.hpp =====

#ifdef DEBUGF
#include  "cpl/template/debug.hpp"
#else
#define DBG(x) (void) 0
#endif

// ===== mod_int.hpp =====

#include <cassert>
#include <iostream>
#include <type_traits>

// ===== utils.hpp =====

constexpr bool is_prime(unsigned n) {
    if (n == 0 || n == 1) {
        return false;
    }
    for (unsigned i = 2; i * i <= n; ++i) {
        if (n % i == 0) {
            return false;
        }
    }
    return true;
}

constexpr unsigned mod_pow(unsigned x, unsigned y, unsigned mod) {
    unsigned ret = 1, self = x;
    while (y != 0) {
        if (y & 1) {
            ret = static_cast<unsigned>(static_cast<unsigned long long>(ret) * self % mod);
        }
        self = static_cast<unsigned>(static_cast<unsigned long long>(self) * self % mod);
        y /= 2;
    }
    return ret;
}

template <unsigned mod>
constexpr unsigned primitive_root() {
    static_assert(is_prime(mod), "`mod` must be a prime number.");
    if (mod == 2) {
        return 1;
    }

    unsigned primes[32] = {};
    int it = 0;
    {
        unsigned m = mod - 1;
        for (unsigned i = 2; i * i <= m; ++i) {
            if (m % i == 0) {
                primes[it++] = i;
                while (m % i == 0) {
                    m /= i;
                }
            }
        }
        if (m != 1) {
            primes[it++] = m;
        }
    }
    for (unsigned i = 2; i < mod; ++i) {
        bool ok = true;
        for (int j = 0; j < it; ++j) {
            if (mod_pow(i, (mod - 1) / primes[j], mod) == 1) {
                ok = false;
                break;
            }
        }
        if (ok)
            return i;
    }
    return 0;
}

// y >= 1
template <typename T>
constexpr T safe_mod(T x, T y) {
    x %= y;
    if (x < 0) {
        x += y;
    }
    return x;
}

// y != 0
template <typename T>
constexpr T floor_div(T x, T y) {
    if (y < 0) {
        x *= -1;
        y *= -1;
    }
    if (x >= 0) {
        return x / y;
    } else {
        return -((-x + y - 1) / y);
    }
}

// y != 0
template <typename T>
constexpr T ceil_div(T x, T y) {
    if (y < 0) {
        x *= -1;
        y *= -1;
    }
    if (x >= 0) {
        return (x + y - 1) / y;
    } else {
        return -(-x / y);
    }
}
// ===== utils.hpp =====

template <unsigned mod>
class ModInt {
    static_assert(mod != 0, "`mod` must not be equal to 0.");
    static_assert(
        mod < (1u << 31),
        "`mod` must be less than (1u << 31) = 2147483648.");

    unsigned val;

public:
    constexpr ModInt() : val(0) {}
    template <typename T>
    constexpr ModInt(T x) : val(static_cast<unsigned>(safe_mod(x, static_cast<T>(mod)))) {}

    static constexpr ModInt raw(unsigned x) {
        ModInt<mod> ret;
        ret.val = x;
        return ret;
    }

    constexpr unsigned get_val() const {
        return val;
    }

    constexpr ModInt operator+() const {
        return *this;
    }
    constexpr ModInt operator-() const {
        return ModInt<mod>(0u) - *this;
    }

    constexpr ModInt &operator+=(const ModInt &rhs) {
        val += rhs.val;
        if (val >= mod)
            val -= mod;
        return *this;
    }
    constexpr ModInt &operator-=(const ModInt &rhs) {
        if (val < rhs.val)
            val += mod;
        val -= rhs.val;
        return *this;
    }
    constexpr ModInt &operator*=(const ModInt &rhs) {
        val = (unsigned long long)val * rhs.val % mod;
        return *this;
    }
    constexpr ModInt &operator/=(const ModInt &rhs) {
        val = (unsigned long long)val * rhs.inv().val % mod;
        return *this;
    }

    friend constexpr ModInt operator+(const ModInt &lhs, const ModInt &rhs) {
        return ModInt<mod>(lhs) += rhs;
    }
    friend constexpr ModInt operator-(const ModInt &lhs, const ModInt &rhs) {
        return ModInt<mod>(lhs) -= rhs;
    }
    friend constexpr ModInt operator*(const ModInt &lhs, const ModInt &rhs) {
        return ModInt<mod>(lhs) *= rhs;
    }
    friend constexpr ModInt operator/(const ModInt &lhs, const ModInt &rhs) {
        return ModInt<mod>(lhs) /= rhs;
    }

    constexpr ModInt pow(unsigned long long x) const {
        ModInt<mod> ret = ModInt<mod>::raw(1);
        ModInt<mod> self = *this;
        while (x != 0) {
            if (x & 1)
                ret *= self;
            self *= self;
            x >>= 1;
        }
        return ret;
    }
    constexpr ModInt inv() const {
        static_assert(is_prime(mod), "`mod` must be a prime number.");
        assert(val != 0);
        return this->pow(mod - 2);
    }

    friend std::istream &operator>>(std::istream &is, ModInt<mod> &x) {
        is >> x.val;
        x.val %= mod;
        return is;
    }

    friend std::ostream &operator<<(std::ostream &os, const ModInt<mod> &x) {
        os << x.val;
        return os;
    }

    friend bool operator==(const ModInt &lhs, const ModInt &rhs) {
        return lhs.val == rhs.val;
    }
    
    friend bool operator!=(const ModInt &lhs, const ModInt &rhs) {
        return lhs.val != rhs.val;
    }
};

[[maybe_unused]] constexpr unsigned mod998244353 = 998244353;
[[maybe_unused]] constexpr unsigned mod1000000007 = 1000000007;

// ===== mod_int.hpp =====

using Mint = ModInt<mod1000000007>;

// ===== fenwick_tree.hpp =====

#include <cassert>
#include <vector>

// ===== operations.hpp =====

#include <limits>
#include <utility>

template <typename T>
struct Add {
    using Value = T;
    static Value id() {
        return T(0);
    }
    static Value op(const Value &lhs, const Value &rhs) {
        return lhs + rhs;
    }
    static Value inv(const Value &x) {
        return -x;
    }
};

template <typename T>
struct Mul {
    using Value = T;
    static Value id() {
        return Value(1);
    }
    static Value op(const Value &lhs, const Value &rhs) {
        return lhs * rhs;
    }
    static Value inv(const Value &x) {
        return Value(1) / x;
    }
};

template <typename T>
struct Min {
    using Value = T;
    static Value id() {
        return std::numeric_limits<T>::max();
    }
    static Value op(const Value &lhs, const Value &rhs) {
        return std::min(lhs, rhs);
    }
};

template <typename T>
struct Max {
    using Value = T;
    static Value id() {
        return std::numeric_limits<Value>::min();
    }
    static Value op(const Value &lhs, const Value &rhs) {
        return std::max(lhs, rhs);
    }
};

template <typename T>
struct Xor {
    using Value = T;
    static Value id() {
        return T(0);
    }
    static Value op(const Value &lhs, const Value &rhs) {
        return lhs ^ rhs;
    }
    static Value inv(const Value &x) {
        return x;
    }
};

template <typename Monoid>
struct Reversible {
    using Value = std::pair<typename Monoid::Value, typename Monoid::Value>;
    static Value id() {
        return Value(Monoid::id(), Monoid::id());
    }
    static Value op(const Value &v1, const Value &v2) {
        return Value(
            Monoid::op(v1.first, v2.first),
            Monoid::op(v2.second, v1.second));
    }
};

// ===== operations.hpp =====

template <typename CommutativeGroup>
class FenwickTree {
public:
    using Value = typename CommutativeGroup::Value;

private:
    std::vector<Value> data;

public:
    FenwickTree(int n) : data(n, CommutativeGroup::id()) {}

    void add(int idx, const Value &x) {
        assert(idx >= 0 && idx < static_cast<int>(data.size()));
        for (; idx < static_cast<int>(data.size()); idx |= idx + 1) {
            data[idx] = CommutativeGroup::op(data[idx], x);
        }
    }

    Value sum(int r) const {
        assert(r >= 0 && r <= static_cast<int>(data.size()));
        Value ret = CommutativeGroup::id();
        for (; r > 0; r &= r - 1) {
            ret = CommutativeGroup::op(ret, data[r - 1]);
        }
        return ret;
    }

    Value sum(int l, int r) const {
        assert(l >= 0 && l <= r && r <= static_cast<int>(data.size()));
        return CommutativeGroup::op(sum(r), CommutativeGroup::inv(sum(l)));
    }
};
// ===== fenwick_tree.hpp =====

int main() {
    i32 n;
    cin >> n;
    Vec<i32> a(n);
    REP(i, n) {
        cin >> a[i];
    }
    
    Vec<Mint> pow2(n + 1);
    pow2[0] = Mint(1);
    REP(i, 1, n + 1) {
        pow2[i] = pow2[i - 1] * Mint(2);
    }
    DBG(pow2);
    
    Vec<i32> idx_l(n);
    iota(ALL(idx_l), 0);
    sort(ALL(idx_l), [&](i32 i, i32 j) -> bool {
        if (a[i] != a[j]) {
            return a[i] < a[j];
        } else {
            return i < j;
        }
    });
    Vec<i32> idx_r(n);
    iota(ALL(idx_r), 0);
    sort(ALL(idx_r), [&](i32 i, i32 j) -> bool {
        if (a[i] != a[j]) {
            return a[i] < a[j];
        } else {
            return i > j;
        }
    });
    DBG(idx_l);
    DBG(idx_r);
    
    Vec<Mint> less_l(n), less_r(n), greater_l(n), greater_r(n);
    
    FenwickTree<Add<Mint>> fw(n);
    for (i32 i : idx_r) {
        fw.add(i, pow2[i]);
        less_l[i] = fw.sum(i);
    }
    fw = FenwickTree<Add<Mint>>(n);
    for (i32 i : idx_l) {
        fw.add(i, pow2[n - 1 - i]);
        less_r[i] = fw.sum(i + 1, n);
    }
    reverse(ALL(idx_l));
    reverse(ALL(idx_r));
    swap(idx_l, idx_r);
    fw = FenwickTree<Add<Mint>>(n);
    for (i32 i : idx_r) {
        fw.add(i, pow2[i]);
        greater_l[i] = fw.sum(i);
    }
    fw = FenwickTree<Add<Mint>>(n);
    for (i32 i : idx_l) {
        fw.add(i, pow2[n - 1 - i]);
        greater_r[i] = fw.sum(i + 1, n);
    }
    DBG(less_l);
    DBG(less_r);
    DBG(greater_l);
    DBG(greater_r);
    
    Mint ans;
    REP(i, n) {
        ans += less_l[i] * less_r[i] + greater_l[i] * greater_r[i];
    }
    cout << ans << '\n';
}