結果

問題 No.1261 数字集め
ユーザー 👑 hos.lyrichos.lyric
提出日時 2020-10-16 22:56:10
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 1,292 ms / 8,000 ms
コード長 4,623 bytes
コンパイル時間 1,349 ms
コンパイル使用メモリ 107,940 KB
実行使用メモリ 30,848 KB
最終ジャッジ日時 2024-07-21 04:13:42
合計ジャッジ時間 75,622 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge3
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ファイルパターン 結果
other AC * 94
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 <cassert>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <functional>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

using Int = long long;

template <class T1, class T2> ostream &operator<<(ostream &os, const pair<T1, T2> &a) { return os << "(" << a.first << ", " << a.second << ")"; };
template <class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; }
template <class T> bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; }
template <class T> bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; }


template<int M_> struct ModInt {
  static constexpr int M = M_;
  int x;
  constexpr ModInt() : x(0) {}
  constexpr ModInt(long long x_) : x(x_ % M) { if (x < 0) x += M; }
  ModInt &operator+=(const ModInt &a) { x += a.x; if (x >= M) x -= M; return *this; }
  ModInt &operator-=(const ModInt &a) { x -= a.x; if (x < 0) x += M; return *this; }
  ModInt &operator*=(const ModInt &a) { x = static_cast<int>((static_cast<long long>(x) * a.x) % M); return *this; }
  ModInt &operator/=(const ModInt &a) { return (*this *= a.inv()); }
  ModInt operator+(const ModInt &a) const { return (ModInt(*this) += a); }
  ModInt operator-(const ModInt &a) const { return (ModInt(*this) -= a); }
  ModInt operator*(const ModInt &a) const { return (ModInt(*this) *= a); }
  ModInt operator/(const ModInt &a) const { return (ModInt(*this) /= a); }
  ModInt operator-() const { return ModInt(-x); }
  ModInt pow(long long e) const {
    if (e < 0) return inv().pow(-e);
    ModInt x2 = x, xe = 1;
    for (; e; e >>= 1) {
      if (e & 1) xe *= x2;
      x2 *= x2;
    }
    return xe;
  }
  ModInt inv() const {
    int a = x, b = M, y = 1, z = 0, t;
    for (; ; ) {
      t = a / b; a -= t * b;
      if (a == 0) {
        assert(b == 1 || b == -1);
        return ModInt(b * z);
      }
      y -= t * z;
      t = b / a; b -= t * a;
      if (b == 0) {
        assert(a == 1 || a == -1);
        return ModInt(a * y);
      }
      z -= t * y;
    }
  }
  friend ModInt operator+(long long a, const ModInt &b) { return (ModInt(a) += b); }
  friend ModInt operator-(long long a, const ModInt &b) { return (ModInt(a) -= b); }
  friend ModInt operator*(long long a, const ModInt &b) { return (ModInt(a) *= b); }
  friend std::ostream &operator<<(std::ostream &os, const ModInt &a) { return os << a.x; }
};

constexpr int MO = 1000000007;
using Mint = ModInt<MO>;

constexpr int LIM = 1'000'010;
Mint inv[LIM], fac[LIM], invFac[LIM];

void prepare() {
  inv[1] = 1;
  for (int i = 2; i < LIM; ++i) {
    inv[i] = -(Mint::M / i) * inv[Mint::M % i];
  }
  fac[0] = invFac[0] = 1;
  for (int i = 1; i < LIM; ++i) {
    fac[i] = fac[i - 1] * i;
    invFac[i] = invFac[i - 1] * inv[i];
  }
}
Mint binom(Int n, Int k) {
  if (0 <= k && k <= n) {
    assert(n < LIM);
    return fac[n] * invFac[k] * invFac[n - k];
  } else {
    return 0;
  }
}


Mint getInv(int d) {
  return (d < 0) ? -inv[-d] : inv[d];
}

int N;
Int M;
vector<int> A;
int Q;
vector<int> X, Y;

vector<Mint> AA;

Mint ans;
vector<int> goal;
vector<Mint> sums;

Mint calc(int u, int v) {
  const int a = A[u], b = A[v], c = A[N];
  const Mint aa = AA[u], bb = AA[v], cc = AA[N];
  Mint ret = -(aa * (b - c) + bb * (c - a) + cc * (a - b));
  ret *= getInv(a - b);
  ret *= getInv(b - c);
  ret *= getInv(c - a);
  return ret;
}

void add(int u, int v) {
  if (v == N) {
    ans += sums[u];
    goal[u] = 1;
  } else {
    const Mint here = calc(u, v);
    if (goal[v]) {
      ans += here;
    }
    sums[v] += here;
  }
}

int main() {
  prepare();
  
  for (; ~scanf("%d%lld", &N, &M); ) {
    A.resize(N + 1);
    for (int u = 2; u <= N; ++u) {
      scanf("%d", &A[u]);
      --A[u];
    }
    scanf("%d", &Q);
    X.resize(Q);
    Y.resize(Q);
    for (int q = 0; q < Q; ++q) {
      scanf("%d%d", &X[q], &Y[q]);
    }
    
    AA.assign(N + 1, 0);
    for (int u = 2; u <= N; ++u) {
      AA[u] = Mint(A[u]).pow((M - 3) + 2);
    }
    
    ans = 0;
    goal.assign(N + 1, 0);
    sums.assign(N + 1, 0);
    
    for (int u = 2; u <= N; ++u) {
      for (int v = 2 * u; v <= N; v += u) {
        add(u, v);
      }
    }
    printf("%d\n", ans.x);
    for (int q = 0; q < Q; ++q) {
      add(X[q], Y[q]);
      printf("%d\n", ans.x);
    }
  }
  return 0;
}
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