結果

問題 No.2440 Accuracy of Integer Division Approximate Functions
ユーザー hos.lyric
提出日時 2023-08-24 21:12:57
言語 D
(dmd 2.109.1)
結果
AC  
実行時間 685 ms / 2,000 ms
コード長 2,591 bytes
コンパイル時間 2,475 ms
コンパイル使用メモリ 173,244 KB
実行使用メモリ 5,248 KB
最終ジャッジ日時 2024-12-23 07:12:16
合計ジャッジ時間 11,877 ms
ジャッジサーバーID
(参考情報)
judge4 / judge1
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ファイルパターン 結果
sample AC * 1
other AC * 20
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 #

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; }
real readReal() { return readToken.to!real; }

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)); }


// floor(a / b)
Int divFloor(Int)(Int a, Int b) {
  return a / b - (((a ^ b) < 0 && a % b != 0) ? 1 : 0);
}

// sum_{x=l}^r floor((a x + b) / m)
// m > 0
BigInt sumFloors(BigInt m, BigInt a, BigInt b, BigInt l, BigInt r)
in {
  assert(m > 0, "sumFloors: m > 0 must hold");
}
do {
  BigInt sum;
  for (; l <= r; ) {
    const q = divFloor(a, m);
    const aa = a - q * m;
    const ll = divFloor(aa * l + b, m) + 1;
    const rr = divFloor(aa * r + b, m);
    // TODO: overflow if ll or rr is big in recursion
    sum += q * ((r + 1) * r / 2 - l * (l - 1) / 2) + r * rr - (l - 1) * (ll - 1) + (rr - ll + 1);
    a = m; m = aa; l = -rr; r = -ll;
  }
  return sum;
}


void main() {
  try {
    for (; ; ) {
      const numCases = readInt;
      foreach (caseId; 0 .. numCases) {
        BigInt N = readLong;
        const BigInt D = readLong;
        const BigInt M = readLong;
        const S = readInt;
        const T = BigInt(1) << S;
        
        const denom = T - M * D;
        if (denom != 0) {
          chmin(N, D * T / abs(denom));
        }
        debug {
          writeln([N, D, M, T]);
        }
        
        BigInt ans;
        if (1 <= N) {
          ans += sumFloors(D, BigInt(1), BigInt(0), BigInt(1), N);
          ans -= sumFloors(T, M, BigInt(0), BigInt(1), N);
        }
        ans = abs(ans);
        ans = N - ans;
        writeln(ans);
      }
    }
  } catch (EOFException e) {
  }
}
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