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ID题目提交者结果用时内存语言文件大小提交时间测评时间
#320993#8211. Enumerating Substringsucup-team087#AC ✓30ms30644kbC++146.0kb2024-02-04 01:46:352024-02-04 01:46:35

Judging History

你现在查看的是最新测评结果

  • [2024-02-04 01:46:35]
  • 评测
  • 测评结果:AC
  • 用时:30ms
  • 内存:30644kb
  • [2024-02-04 01:46:35]
  • 提交

answer

#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 <limits>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#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> ostream &operator<<(ostream &os, const vector<T> &as) { const int sz = as.size(); os << "["; for (int i = 0; i < sz; ++i) { if (i >= 256) { os << ", ..."; break; } if (i > 0) { os << ", "; } os << as[i]; } return os << "]"; }
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; }
#define COLOR(s) ("\x1b[" s "m")

////////////////////////////////////////////////////////////////////////////////
template <unsigned M_> struct ModInt {
  static constexpr unsigned M = M_;
  unsigned x;
  constexpr ModInt() : x(0U) {}
  constexpr ModInt(unsigned x_) : x(x_ % M) {}
  constexpr ModInt(unsigned long long x_) : x(x_ % M) {}
  constexpr ModInt(int x_) : x(((x_ %= static_cast<int>(M)) < 0) ? (x_ + static_cast<int>(M)) : x_) {}
  constexpr ModInt(long long x_) : x(((x_ %= static_cast<long long>(M)) < 0) ? (x_ + static_cast<long long>(M)) : x_) {}
  ModInt &operator+=(const ModInt &a) { x = ((x += a.x) >= M) ? (x - M) : x; return *this; }
  ModInt &operator-=(const ModInt &a) { x = ((x -= a.x) >= M) ? (x + M) : x; return *this; }
  ModInt &operator*=(const ModInt &a) { x = (static_cast<unsigned long long>(x) * a.x) % M; return *this; }
  ModInt &operator/=(const ModInt &a) { return (*this *= a.inv()); }
  ModInt pow(long long e) const {
    if (e < 0) return inv().pow(-e);
    ModInt a = *this, b = 1U; for (; e; e >>= 1) { if (e & 1) b *= a; a *= a; } return b;
  }
  ModInt inv() const {
    unsigned a = M, b = x; int y = 0, z = 1;
    for (; b; ) { const unsigned q = a / b; const unsigned c = a - q * b; a = b; b = c; const int w = y - static_cast<int>(q) * z; y = z; z = w; }
    assert(a == 1U); return ModInt(y);
  }
  ModInt operator+() const { return *this; }
  ModInt operator-() const { ModInt a; a.x = x ? (M - x) : 0U; return 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 ModInt &a) const { return (ModInt(*this) /= a); }
  template <class T> friend ModInt operator+(T a, const ModInt &b) { return (ModInt(a) += b); }
  template <class T> friend ModInt operator-(T a, const ModInt &b) { return (ModInt(a) -= b); }
  template <class T> friend ModInt operator*(T a, const ModInt &b) { return (ModInt(a) *= b); }
  template <class T> friend ModInt operator/(T a, const ModInt &b) { return (ModInt(a) /= b); }
  explicit operator bool() const { return x; }
  bool operator==(const ModInt &a) const { return (x == a.x); }
  bool operator!=(const ModInt &a) const { return (x != a.x); }
  friend std::ostream &operator<<(std::ostream &os, const ModInt &a) { return os << a.x; }
};
////////////////////////////////////////////////////////////////////////////////

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

constexpr int LIM_INV = 2'000'010;
Mint inv[LIM_INV], fac[LIM_INV], invFac[LIM_INV];

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


int main() {
  prepare();
  
  int N, M, K;
  for (; ~scanf("%d%d%d", &N, &M, &K); ) {
    // x^M / (1-Kx)^2
    vector<Mint> hs(N + 1, 0);
    hs[M] = 1;
    for (int i = 1; i <= N; ++i) hs[i] += hs[i - 1] * K;
    for (int i = 1; i <= N; ++i) hs[i] += hs[i - 1] * K;
// cerr<<"hs = "<<hs<<endl;
    
    vector<Mint> invTwo(M + 1);
    invTwo[0] = 1;
    for (int i = 1; i <= M; ++i) {
      invTwo[i] = invTwo[i - 1] * inv[2];
    }
    vector<Mint> under(M + 1);
    under[0] = 1;
    for (int i = 0; i < M; ++i) {
      under[i + 1] = under[i] * Mint(K - i);
    }
    
    Mint all0 = 0;
    for (int b = 0; b <= M/2; ++b) {
      const int a = M - 2*b;
      all0 += under[a + b] * invFac[a] * invFac[b] * fac[a + 2*b] * invTwo[b];
    }
    
    vector<Mint> ways(M/2 + 1, 0);
    Mint way0 = all0;
    for (int m = 1; m <= M/2; ++m) {
      for (int b = 0; b <= (M-2*m)/2; ++b) {
        const int a = (M-2*m) - 2*b;
        ways[m] += under[m + a + b] * invFac[a] * invFac[b] * fac[a + 2*b] * invTwo[b];
      }
      way0 -= ways[m];
    }
// cerr<<"under = "<<under<<endl;
// cerr<<"all0 = "<<all0<<endl;
// cerr<<"ways = "<<ways<<endl;
// cerr<<"way0 = "<<way0<<endl;
    
    Mint ans = 0;
    ans += way0 * hs[N];
    for (int m = 1; m <= M/2; ++m) {
      // * 1 / (1+x^(M-m))
      Mint sum = 0;
      for (int j = 0; (M-m) * j <= N; ++j) {
        sum += (j&1?-1:+1) * hs[N - (M-m) * j];
      }
      ans += ways[m] * sum;
    }
    printf("%u\n", ans.x);
  }
  return 0;
}

这程序好像有点Bug,我给组数据试试?

詳細信息

Test #1:

score: 100
Accepted
time: 13ms
memory: 27260kb

input:

4 2 3

output:

228

result:

ok 1 number(s): "228"

Test #2:

score: 0
Accepted
time: 30ms
memory: 30536kb

input:

999999 1999 12345678

output:

52352722

result:

ok 1 number(s): "52352722"

Test #3:

score: 0
Accepted
time: 12ms
memory: 27264kb

input:

7 4 2

output:

182

result:

ok 1 number(s): "182"

Test #4:

score: 0
Accepted
time: 20ms
memory: 27232kb

input:

4 3 4

output:

480

result:

ok 1 number(s): "480"

Test #5:

score: 0
Accepted
time: 10ms
memory: 27264kb

input:

3 1 1

output:

3

result:

ok 1 number(s): "3"

Test #6:

score: 0
Accepted
time: 16ms
memory: 27208kb

input:

5 5 1

output:

0

result:

ok 1 number(s): "0"

Test #7:

score: 0
Accepted
time: 16ms
memory: 27152kb

input:

7 4 3

output:

5784

result:

ok 1 number(s): "5784"

Test #8:

score: 0
Accepted
time: 16ms
memory: 27204kb

input:

5 2 4

output:

3932

result:

ok 1 number(s): "3932"

Test #9:

score: 0
Accepted
time: 16ms
memory: 27548kb

input:

8 2 2

output:

1522

result:

ok 1 number(s): "1522"

Test #10:

score: 0
Accepted
time: 20ms
memory: 27232kb

input:

8 1 2

output:

2048

result:

ok 1 number(s): "2048"

Test #11:

score: 0
Accepted
time: 20ms
memory: 27560kb

input:

7 5 3

output:

2430

result:

ok 1 number(s): "2430"

Test #12:

score: 0
Accepted
time: 12ms
memory: 27208kb

input:

10 4 3

output:

272004

result:

ok 1 number(s): "272004"

Test #13:

score: 0
Accepted
time: 26ms
memory: 29456kb

input:

675978 614 2

output:

0

result:

ok 1 number(s): "0"

Test #14:

score: 0
Accepted
time: 15ms
memory: 27668kb

input:

244613 38 1

output:

0

result:

ok 1 number(s): "0"

Test #15:

score: 0
Accepted
time: 20ms
memory: 27344kb

input:

186293 1462 1

output:

0

result:

ok 1 number(s): "0"

Test #16:

score: 0
Accepted
time: 21ms
memory: 27328kb

input:

24867 886 1

output:

0

result:

ok 1 number(s): "0"

Test #17:

score: 0
Accepted
time: 27ms
memory: 30512kb

input:

976164 1014 2

output:

0

result:

ok 1 number(s): "0"

Test #18:

score: 0
Accepted
time: 23ms
memory: 27784kb

input:

179356 2 716844809

output:

577866092

result:

ok 1 number(s): "577866092"

Test #19:

score: 0
Accepted
time: 22ms
memory: 29200kb

input:

621001 130 310625363

output:

892869197

result:

ok 1 number(s): "892869197"

Test #20:

score: 0
Accepted
time: 26ms
memory: 29436kb

input:

678862 850 754662812

output:

582264789

result:

ok 1 number(s): "582264789"

Test #21:

score: 0
Accepted
time: 30ms
memory: 29152kb

input:

650845 978 348443366

output:

825425732

result:

ok 1 number(s): "825425732"

Test #22:

score: 0
Accepted
time: 25ms
memory: 29508kb

input:

669914 402 87448112

output:

318098088

result:

ok 1 number(s): "318098088"

Test #23:

score: 0
Accepted
time: 22ms
memory: 30644kb

input:

998593 530 681228665

output:

408255654

result:

ok 1 number(s): "408255654"

Test #24:

score: 0
Accepted
time: 27ms
memory: 27972kb

input:

369361 1954 125266115

output:

509912384

result:

ok 1 number(s): "509912384"

Test #25:

score: 0
Accepted
time: 30ms
memory: 30192kb

input:

900226 1378 424079373

output:

406320917

result:

ok 1 number(s): "406320917"

Test #26:

score: 0
Accepted
time: 23ms
memory: 28028kb

input:

334887 1506 17859926

output:

503264679

result:

ok 1 number(s): "503264679"

Test #27:

score: 0
Accepted
time: 29ms
memory: 30372kb

input:

936048 544 53978328

output:

548647866

result:

ok 1 number(s): "548647866"

Test #28:

score: 0
Accepted
time: 23ms
memory: 27568kb

input:

152789 1264 792983073

output:

839541707

result:

ok 1 number(s): "839541707"

Test #29:

score: 0
Accepted
time: 28ms
memory: 29356kb

input:

714493 1392 91796331

output:

721071046

result:

ok 1 number(s): "721071046"

Test #30:

score: 0
Accepted
time: 21ms
memory: 27784kb

input:

269571 816 830801077

output:

330064211

result:

ok 1 number(s): "330064211"

Test #31:

score: 0
Accepted
time: 28ms
memory: 29856kb

input:

845120 944 424581630

output:

348960190

result:

ok 1 number(s): "348960190"

Test #32:

score: 0
Accepted
time: 20ms
memory: 28664kb

input:

533990 368 163586376

output:

522092095

result:

ok 1 number(s): "522092095"

Test #33:

score: 0
Accepted
time: 16ms
memory: 27348kb

input:

181707 1792 462399634

output:

373795106

result:

ok 1 number(s): "373795106"

Test #34:

score: 0
Accepted
time: 24ms
memory: 28312kb

input:

417349 1920 761212891

output:

587051329

result:

ok 1 number(s): "587051329"

Test #35:

score: 0
Accepted
time: 26ms
memory: 28576kb

input:

526583 1344 500217637

output:

108767800

result:

ok 1 number(s): "108767800"

Test #36:

score: 0
Accepted
time: 26ms
memory: 30284kb

input:

867054 769 93998191

output:

239123369

result:

ok 1 number(s): "239123369"

Extra Test:

score: 0
Extra Test Passed