結果

問題 No.2616 中央番目の中央値
ユーザー 👑 hos.lyrichos.lyric
提出日時 2024-01-26 22:29:42
言語 D
(dmd 2.106.1)
結果
AC  
実行時間 104 ms / 2,000 ms
コード長 4,925 bytes
コンパイル時間 1,716 ms
コンパイル使用メモリ 142,208 KB
実行使用メモリ 22,596 KB
最終ジャッジ日時 2024-01-26 22:30:11
合計ジャッジ時間 5,687 ms
ジャッジサーバーID
（参考情報） 		judge11 / judge14
このコードへのチャレンジ
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 19 ms
12,272 KB
testcase_01 AC 19 ms
12,272 KB
testcase_02 AC 18 ms
12,272 KB
testcase_03 AC 18 ms
12,272 KB
testcase_04 AC 18 ms
12,272 KB
testcase_05 AC 18 ms
12,272 KB
testcase_06 AC 18 ms
12,272 KB
testcase_07 AC 18 ms
12,272 KB
testcase_08 AC 19 ms
12,272 KB
testcase_09 AC 18 ms
12,272 KB
testcase_10 AC 18 ms
12,272 KB
testcase_11 AC 18 ms
12,272 KB
testcase_12 AC 18 ms
12,272 KB
testcase_13 AC 18 ms
12,272 KB
testcase_14 AC 19 ms
12,272 KB
testcase_15 AC 20 ms
12,272 KB
testcase_16 AC 22 ms
12,400 KB
testcase_17 AC 24 ms
12,272 KB
testcase_18 AC 29 ms
14,404 KB
testcase_19 AC 41 ms
14,404 KB
testcase_20 AC 41 ms
14,404 KB
testcase_21 AC 72 ms
20,548 KB
testcase_22 AC 101 ms
22,596 KB
testcase_23 AC 103 ms
22,596 KB
testcase_24 AC 79 ms
22,596 KB
testcase_25 AC 80 ms
22,596 KB
testcase_26 AC 102 ms
22,596 KB
testcase_27 AC 101 ms
22,596 KB
testcase_28 AC 101 ms
22,596 KB
testcase_29 AC 101 ms
22,596 KB
testcase_30 AC 100 ms
22,596 KB
testcase_31 AC 98 ms
22,596 KB
testcase_32 AC 103 ms
22,596 KB
testcase_33 AC 100 ms
22,596 KB
testcase_34 AC 104 ms
22,596 KB
testcase_35 AC 102 ms
22,596 KB
testcase_36 AC 99 ms
22,596 KB
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ソースコード

diff # 

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; }

string COLOR(string s = "") { return "\x1b[" ~ s ~ "m"; }

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 = 6 * 10^^5 + 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 bAdd(T)(T[] bit, int pos, T val)
in {
  assert(0 <= pos && pos < bit.length, "bAdd: 0 <= pos < |bit| must hold");
}
do {
  for (int x = pos; x < bit.length; x |= x + 1) {
    bit[x] += val;
  }
}

// sum of [0, pos)
T bSum(T)(T[] bit, int pos)
in {
  assert(0 <= pos && pos <= bit.length, "bSum: 0 <= pos <= |bit| must hold");
}
do {
  T ret = 0;
  for (int x = pos - 1; x >= 0; x = (x & (x + 1)) - 1) {
    ret += bit[x];
  }
  return ret;
}


void main() {
  prepare;
  
  try {
    for (; ; ) {
      const N = readInt;
      auto P = new int[N];
      foreach (i; 0 .. N) {
        P[i] = readInt - 1;
      }
      
      Mint ans;
      auto bit = new int[N];
      foreach (i; 0 .. N) {
        const a = bit.bSum(P[i]);
        const b = i - a;
        const c = P[i] - a;
        const d = (N - 1 - i) - c;
        ans += binom(a + d, a) * binom(b + c, b);
        bit.bAdd(P[i], +1);
      }
      writeln(ans);
    }
  } catch (EOFException e) {
  }
}
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