Submission #635633

#	Time	Username	Problem	Language	Result	Execution time	Memory
635633		Cyanmond	Party (INOI20_party)	C++17	40 / 100	3030 ms	65100 KiB

Main

#include <bits/stdc++.h>

using i64 = long long;

constexpr i64 mod = 1000000007;

i64 nmr(i64 a) {
    a %= mod;
    if (a < 0) a += mod;
    return a;
}

i64 add(i64 a, i64 b) {
    a += b;
    if (a > mod) a -= mod;
    return a;
}
i64 mul(i64 a, i64 b) { return a * b % mod; }
void add_m(i64 &a, i64 b) { a = add(a, b); }
void mul_m(i64 &a, i64 b) { a = mul(a, b); }

i64 inv(i64 x) {
    i64 a = x, b = mod, u = 1, v = 0, t = 0;
    while (b > 0) {
        t = a / b;
        a -= t * b;
        u -= t * v;
        std::swap(a, b);
        std::swap(u, v);
    }
    return nmr(u);
}

constexpr i64 width = 1 << 17;
std::array<i64, width> pa, pb;

void init_p2() {
    pa[0] = 1;
    for (int i = 1; i < width; ++i) pa[i] = mul(pa[i - 1], 2);
    pb[0] = 1;
    const i64 v1 = mul(pa.back(), 2);
    for (int i = 1; i < width; ++i) pb[i] = mul(pb[i - 1], v1);
}

inline i64 pow2(i64 n) {
    static int v1, v2;
    n %= mod - 1;
    v2 = n / width;
    i64 ret = pb[v2];
    n -= width * v2;
    return mul(ret, pa[n]);
}

std::array<std::array<std::array<i64, 200>, 200>, 200> cv_m;

void solve() {
    // Time Complexity O(log^3 N)
    i64 N;
    std::cin >> N;
    // N = 2 ^ k - 1
    int k = 0;
    while ((1ll << k) - 1 < N) ++k;
 
    std::vector<i64> red_vs = {N + 1};
    while (red_vs.back() != 1) {
        red_vs.push_back(red_vs.back() / 2);
    }
    std::reverse(red_vs.begin(), red_vs.end());

    auto count_vs = [&](i64 v, int d, int u) -> i64 {
        if (u == 0) return 1;
        static int l, r, t, q;
        static i64 ret, ln, wn;

        if (cv_m[k][d][u] != -1) {
            ret = cv_m[k][d][u];
            r = std::min(u, d);
            l = std::max(0, (d + u - k + 2) / 2);
            if (d + u < k) --l;
        } else {
            const auto v2 = v;
            v /= 2;
            --u;
            --d;
            r = std::min(u, d);
            l = std::max(0, (d + u - k + 2) / 2);
            ret = 0;
            if (d != -1) {
                if (l <= r) {
                    if (u == 0) ret = 1;
                    else if (d >= u) {
                        t = u - l;
                        ret |= 1ll << t;
                    } else {
                        t = u - d;
                        q = t + (r - l);
                        ret |= (1ll << q) - 1;
                        ret -= (1ll << (t - 1)) - 1;
                    }
                }
            }
            v = v2;
            ++u;
            ++d;
            ++l;
            ++r;
            if (d + u < k) {
                --l;
                ret += 1ll << u;
            }
            cv_m[k][d][u] = ret;
        }

        t = (d + u - k + 1) / 2;
        if (t < 0) return ret;
        if (d + u - 2 * t != k - 1) {
            return ret;
        }
        if (not(l <= t and t <= r)) {
            return ret;
        }

        ln = 0, wn = 0;
        if (t == 0) {
            v >>= t;
            ln = v << (u - t);
            wn = 1ll << (u - t);
        } else {
            --t;
            v >>= t;
            v ^= 1;
            t += 2;
            ln = v << (u - t);
            wn = 1ll << (u - t);
        }
        ret -= std::max(0ll, std::min(wn, ln + wn - N - 1));
        return ret;
    };

    i64 pow2_N = pow2(N);
    // sa0te
    auto dfs = [&](auto &&self, const int d, const i64 v) -> i64 {
        if (v > N) return 0;
        i64 ret = 0;
        if (red_vs[d] == v) {
            // rec
            add_m(ret, self(self, d + 1, 2 * v));
            add_m(ret, self(self, d + 1, 2 * v + 1));
 
            i64 sum = 0, memo = pow2_N;
            for (int u = 0; u <= d + k; ++u) {
                const i64 count_v = count_vs(v, d, u);
                if (count_v == 0) continue;
                i64 new_memo = pow2(N - sum - count_v);
                add_m(ret, mul(u, add(memo, mod - new_memo)));
                sum += count_v;
                memo = new_memo;
            }
        } else {
            // no rec
            for (int fd = d; fd < k; ++fd) {
                if (v * (1ll << (fd - d)) > N) continue;
                const i64 ms = nmr(1ll << (fd - d));
                i64 msm = -ms;
                i64 sum = 0, memo = pow2_N;
                for (int u = 0; u <= fd + k; ++u) {
                    add_m(msm, ms);
                    const i64 count_v = count_vs(v << (fd - d), fd, u);
                    if (count_v == 0) continue;
                    i64 new_memo = pow2(N - sum - count_v);
                    add_m(ret, mul(msm, add(memo, mod - new_memo)));
                    sum += count_v;
                    memo = new_memo;
                }
            }
        }
 
        return ret;
    };
    const auto res = dfs(dfs, 0, 1);
 
    std::cout << nmr(res * inv(add(pow2(N), mod - 1))) << std::endl;
}
 
int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    init_p2();
    for (auto &a : cv_m) for (auto &b : a) for (auto &c : b) c = -1;
    int Q;
    std::cin >> Q;
    while (Q--) solve();
}

Compilation message (stderr)

Main.cpp: In function 'i64 pow2(i64)':
Main.cpp:46:16: warning: unused variable 'v1' [-Wunused-variable]
   46 |     static int v1, v2;
      |                ^~

• Subtask 1: 7 / 7
• Subtask 2: 0 / 23
• Subtask 3: 33 / 33
• Subtask 4: 0 / 37