結果

問題 No.2384 Permutations of Permutations
ユーザー 👑 hos.lyric
提出日時 2023-07-14 21:51:02
言語 D
(dmd 2.109.1)
結果
AC  
実行時間 37 ms / 2,000 ms
コード長 5,757 bytes
コンパイル時間 3,509 ms
コンパイル使用メモリ 155,904 KB
実行使用メモリ 17,024 KB
最終ジャッジ日時 2024-09-16 06:46:36
合計ジャッジ時間 3,835 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge6
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 2
other AC * 22
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 #
プレゼンテーションモードにする

import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std
    .typecons;
import core.bitop;
class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens
    .popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }
int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; 
    (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }
struct ModInt(uint M_) {
  import std.conv : to;
  alias M = M_;
  uint x;
  this(ModInt a) { x = a.x; }
  this(uint x_) { x = x_ % M; }
  this(ulong x_) { x = cast(uint)(x_ % M); }
  this(int x_) { x = ((x_ %= cast(int)(M)) < 0) ? (x_ + cast(int)(M)) : x_; }
  this(long x_) { x = cast(uint)(((x_ %= cast(long)(M)) < 0) ? (x_ + cast(long)(M)) : x_); }
  ref ModInt opAssign(T)(inout(T) a) if (is(T == uint) || is(T == ulong) || is(T == int) || is(T == long)) { return this = ModInt(a); }
  ref ModInt opOpAssign(string op, T)(T a) {
    static if (is(T == ModInt)) {
      static if (op == "+") { x = ((x += a.x) >= M) ? (x - M) : x; }
      else static if (op == "-") { x = ((x -= a.x) >= M) ? (x + M) : x; }
      else static if (op == "*") { x = cast(uint)((cast(ulong)(x) * a.x) % M); }
      else static if (op == "/") { this *= a.inv(); }
      else static assert(false);
      return this;
    } else static if (op == "^^") {
      if (a < 0) return this = inv()^^(-a);
      ModInt b = this, c = 1U;
      for (long e = a; e; e >>= 1) { if (e & 1) c *= b; b *= b; }
      return this = c;
    } else {
      return mixin("this " ~ op ~ "= ModInt(a)");
    }
  }
  ModInt inv() const {
    uint a = M, b = x; int y = 0, z = 1;
    for (; b; ) { const q = a / b; const c = a - q * b; a = b; b = c; const w = y - cast(int)(q) * z; y = z; z = w; }
    assert(a == 1); return ModInt(y);
  }
  ModInt opUnary(string op)() const {
    static if (op == "+") { return this; }
    else static if (op == "-") { ModInt a; a.x = x ? (M - x) : 0U; return a; }
    else static assert(false);
  }
  ModInt opBinary(string op, T)(T a) const { return mixin("ModInt(this) " ~ op ~ "= a"); }
  ModInt opBinaryRight(string op, T)(T a) const { return mixin("ModInt(a) " ~ op ~ "= this"); }
  bool opCast(T: bool)() const { return (x != 0U); }
  string toString() const { return x.to!string; }
}
enum MO = 998244353;
alias Mint = ModInt!MO;
enum LIM_INV = 10^^6 + 10;
Mint[] inv, fac, invFac;
void prepare() {
  inv = new Mint[LIM_INV];
  fac = new Mint[LIM_INV];
  invFac = new Mint[LIM_INV];
  inv[1] = 1;
  foreach (i; 2 .. LIM_INV) {
    inv[i] = -((Mint.M / i) * inv[cast(size_t)(Mint.M % i)]);
  }
  fac[0] = invFac[0] = 1;
  foreach (i; 1 .. LIM_INV) {
    fac[i] = fac[i - 1] * i;
    invFac[i] = invFac[i - 1] * inv[i];
  }
}
Mint binom(long n, long k) {
  if (n < 0) {
    if (k >= 0) {
      return (-1)^^(k & 1) * binom(-n + k - 1, k);
    } else if (n - k >= 0) {
      return (-1)^^((n - k) & 1) * binom(-k - 1, n - k);
    } else {
      return Mint(0);
    }
  } else {
    if (0 <= k && k <= n) {
      assert(n < LIM_INV);
      return fac[cast(size_t)(n)] * invFac[cast(size_t)(k)] * invFac[cast(size_t)(n - k)];
    } else {
      return Mint(0);
    }
  }
}
void main() {
  prepare;
  
  try {
    for (; ; ) {
      const N = readInt;
      const K = readInt;
      
      Mint ans;
      if (N == 2) {
        // Aut(S[2]) = 1
        ans = 1;
      } else if (N == 6) {
        // Aut(S[6]): sugoi
        if (K == 1) {
          ans = 2 * fac[N];
        } else {
          foreach (spe; 0 .. 2) {
            auto tau = iota(N).array;
            do {
              // sigma = (0 1) ... (K-2 K-1)
              auto ps = iota(N).array;
              if (spe) {
                enum DATA = [
                  [[0, 1], [2, 3], [4, 5]],
                  [[0, 3], [1, 4], [2, 5]],
                  [[0, 1], [2, 4], [3, 5]],
                  [[0, 3], [1, 2], [4, 5]],
                  [[0, 1], [2, 5], [3, 4]],
                ];
                foreach_reverse (x; 0 .. K-1) {
                  foreach (sw; DATA[x]) {
                    swap(ps[sw[0]], ps[sw[1]]);
                  }
                }
              } else {
                foreach_reverse (x; 0 .. K-1) {
                  ps[x] = x + 1;
                }
                ps[K-1] = 0;
              }
              // ps -> tau ps tau^-1
              auto invTau = new int[N];
              foreach (x; 0 .. N) invTau[tau[x]] = x;
              auto qs = new int[N];
              foreach (x; 0 .. N) qs[x] = tau[ps[invTau[x]]];
              bool ok = true;
              foreach (x; 0 .. K-1) ok = ok && (qs[x] == x + 1);
              ok = ok && (qs[K-1] == 0);
              if (ok) {
                ans += 1;
              }
            } while (tau.nextPermutation);
          }
        }
      } else {
        if (K == 1) {
          // F(id) = id
          ans = fac[N];
        } else {
          ans = 1;
          ans *= K;
          ans *= fac[N-K];
        }
      }
      writeln(ans);
    }
  } catch (EOFException e) {
  }
}
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