高速入出力 (utility/fast_io.cpp)

#ifndef H_fast_io
#define H_fast_io

/**
 * @brief 高速入出力
 * @author えびちゃん
 * @see https://qiita.com/rsk0315_h4x/items/17a9cb12e0de5fd918f4
 */

#include <cstddef>
#include <cstdint>
#include <cstdio>
#include <cstring>
#include <limits>
#include <string>
#include <type_traits>
#include <utility>

#include "integer/bit.cpp"

namespace fast {
  static constexpr size_t buf_size = 1 << 17;
  static constexpr size_t margin = 1;
  static char inbuf[buf_size + margin] = {};
  static __attribute__((aligned(8))) char outbuf[buf_size + margin] = {};
  static __attribute__((aligned(8))) char minibuf[32];
  static constexpr size_t int_digits = 20;  // 18446744073709551615
  static constexpr uintmax_t digit_mask = 0x3030303030303030;
  static constexpr uintmax_t first_mask = 0x00FF00FF00FF00FF;
  static constexpr uintmax_t second_mask = 0x0000FFFF0000FFFF;
  static constexpr uintmax_t third_mask = 0x00000000FFFFFFFF;
  static constexpr uintmax_t tenpow[] = {
    1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000,
    1000000000, 10000000000, 100000000000, 1000000000000, 10000000000000,
    100000000000000, 1000000000000000, 10000000000000000, 100000000000000000,
    1000000000000000000, 10000000000000000000u,
  };
  static __attribute__((aligned(8))) char inttab[40000] = {};  // 4-digit integers (10000 many)
  static char S_sep = ' ', S_end = '\n';
  template <typename Tp>
  using enable_if_integral = std::enable_if<std::is_integral<Tp>::value, Tp>;

  class scanner {
    char* pos = inbuf;
    char* endpos = inbuf + buf_size;

    void M_read_from_stdin() {
      endpos = inbuf + fread(pos, 1, buf_size, stdin);
    }
    void M_reread_from_stdin() {
      ptrdiff_t len = endpos - pos;
      if (!(inbuf + len <= pos)) return;
      memcpy(inbuf, pos, len);
      char* tmp = inbuf + len;
      endpos = tmp + fread(tmp, 1, buf_size-len, stdin);
      *endpos = 0;
      pos = inbuf;
    }

  public:
    scanner() { M_read_from_stdin(); }

    template <typename Integral,
              typename enable_if_integral<Integral>::type* = nullptr>
    void scan_parallel(Integral& x) {
      if (__builtin_expect(endpos <= pos + int_digits, 0))
        M_reread_from_stdin();
      bool ends = false;
      typename std::make_unsigned<Integral>::type y = 0;
      bool neg = false;
      if (std::is_signed<Integral>::value && *pos == '-') {
        neg = true;
        ++pos;
      }
      do {
        memcpy(minibuf, pos, 8);
        intmax_t c = *(intmax_t*)minibuf;
        intmax_t d = (c & digit_mask) ^ digit_mask;
        int skip = 8;
        int shift = 8;
        if (d) {
          int ctz = countr_zero<uintmax_t>(d);
          if (ctz == 4) break;
          c &= (1L << (ctz-5)) - 1;
          int discarded = (68-ctz) / 8;
          shift -= discarded;
          c <<= discarded * 8;
          skip -= discarded;
          ends = true;
        }
        c |= digit_mask;
        c ^= digit_mask;
        c = ((c >> 8) + c*10) & first_mask;
        c = ((c >> 16) + c*100) & second_mask;
        c = ((c >> 32) + c*10000) & third_mask;
        y = y*tenpow[shift] + c;
        pos += skip;
      } while (!ends);
      x = (neg? -y: y);
      ++pos;
    }

    template <typename Integral,
              typename enable_if_integral<Integral>::type* = nullptr>
    void scan_serial(Integral& x) {
      if (__builtin_expect(endpos <= pos + int_digits, 0))
        M_reread_from_stdin();
      bool neg = false;
      if (std::is_signed<Integral>::value && *pos == '-') {
        neg = true;
        ++pos;
      }
      typename std::make_unsigned<Integral>::type y = *pos-'0';
      while (*++pos >= '0') y = 10*y + *pos-'0';
      x = (neg? -y: y);
      ++pos;
    }

    template <typename Integral,
              typename enable_if_integral<Integral>::type* = nullptr>
    // Use scan_parallel(x) only when x may be too large (about 10^12).
    // Otherwise, even when x <= 10^9, scan_serial(x) may be faster.
    void scan(Integral& x) { scan_serial(x); }

    void scan_serial(std::string& s) {
      // until first whitespace
      s = "";
      do {
        char* startpos = pos;
        while (*pos > ' ') ++pos;
        s += std::string(startpos, pos);
        if (*pos != 0) {
          ++pos;  // skip the space
          break;
        }
        M_reread_from_stdin();
      } while (true);
    }

    void scan(std::string& s) { scan_serial(s); }

    template <typename Tp, typename... Args>
    void scan(Tp& x, Args&&... xs) {
      scan(x);
      scan(std::forward<Args>(xs)...);
    }
  };

  class printer {
    char* pos = outbuf;

    void M_flush_stdout() {
      fwrite(outbuf, 1, pos-outbuf, stdout);
      pos = outbuf;
    }

    static int S_int_digits(uintmax_t n) {
      if (n < tenpow[16]) {  // 1
        if (n < tenpow[8]) {  // 2
          if (n < tenpow[4]) {  // 3
            if (n < tenpow[2]) {  // 4
              if (n < tenpow[1]) return 1;  // 5
              return 2;  // 5
            }
            if (n < tenpow[3]) return 3;  // 4
            return 4;  // 4
          }
          if (n < tenpow[6]) {  // 4
            if (n < tenpow[5]) return 5;  // 5
            return 6;  // 5
          }
          if (n < tenpow[7]) return 7;  // 5
          return 8;  // 5
        }
        if (n < tenpow[12]) {  // 3
          if (n < tenpow[10]) {  // 4
            if (n < tenpow[9]) return 9;  // 5
            return 10;  // 5
          }
          if (n < tenpow[11]) return 11;  // 5
          return 12;  // 5
        }
        if (n < tenpow[14]) {  // 4
          if (n < tenpow[13]) return 13;  // 5
          return 14;  // 5
        }
        if (n < tenpow[15]) return 15;  // 5
        return 16;  // 5
      }
      if (n < tenpow[18]) {  // 2
        if (n < tenpow[17]) return 17;  // 3
        return 18;  // 3
      }
      return 19;  // 2
      if (n < tenpow[19]) return 19;  // 3
      return 20;  // 3
    }

    void M_precompute() {
      uintmax_t const digit1 = 0x0200000002000000;
      uintmax_t const digit2 = 0xf600fffff6010000;
      uintmax_t const digit3 = 0xfff600fffff60100;
      uintmax_t const digit4 = 0xfffff600fffff601;
      uintmax_t counter = 0x3130303030303030;
      for (int i = 0, i4 = 0; i4 < 10; ++i4, counter += digit4)
        for (int i3 = 0; i3 < 10; ++i3, counter += digit3)
          for (int i2 = 0; i2 < 10; ++i2, counter += digit2)
            for (int i1 = 0; i1 < 5; ++i1, ++i, counter += digit1)
              *((uintmax_t*)inttab + i) = counter;
    }

  public:
    printer() { M_precompute(); }
    ~printer() { M_flush_stdout(); }

    void print(char c) {
      if (__builtin_expect(pos + 1 >= outbuf + buf_size, 0)) M_flush_stdout();
      *pos++ = c;
    }

    template <size_t N>
    void print(char const(&s)[N]) {
      if (__builtin_expect(pos + N >= outbuf + buf_size, 0)) M_flush_stdout();
      memcpy(pos, s, N-1);
      pos += N-1;
    }

    void print(char const* s) {
      // FIXME: strlen や memcpy などで定数倍高速化したい
      while (*s != 0) {
        *pos++ = *s++;
        if (pos == outbuf + buf_size) M_flush_stdout();
      }
    }

    void print(std::string const& s) { print(s.data()); }

    template <typename Integral,
              typename enable_if_integral<Integral>::type* = nullptr>
    void print(Integral x) {
      if (__builtin_expect(pos + int_digits >= outbuf + buf_size, 0))
        M_flush_stdout();
      if (x == 0) {
        *pos++ = '0';
        return;
      }
      if (x < 0) {
        *pos++ = '-';
        if (__builtin_expect(x == std::numeric_limits<Integral>::min(), 0)) {
          switch (sizeof x) {
          case 2: print("32768"); return;
          case 4: print("2147483648"); return;
          case 8: print("9223372036854775808"); return;
          }
        }
        x = -x;
      }

      typename std::make_unsigned<Integral>::type y = x;
      int len = S_int_digits(y);
      pos += len;
      char* tmp = pos;
      int w = (pos - outbuf) & 3;
      if (w > len) w = len;
      for (int i = w; i > 0; --i) {
        *--tmp = y % 10 + '0';
        y /= 10;
      }
      len -= w;
      while (len >= 4) {
        tmp -= 4;
        *(unsigned*)tmp = *((unsigned*)inttab + (y % 10000));
        len -= 4;
        if (len) y /= 10000;
      }
      while (len-- > 0) {
        *--tmp = y % 10 + '0';
        y /= 10;
      }
    }

    template <typename Tp, typename... Args>
    void print(Tp const& x, Args&&... xs) {
      if (sizeof...(Args) > 0) {
        print(x);
        print(S_sep);
        print(std::forward<Args>(xs)...);
      }
    }

    template <typename Tp>
    void println(Tp const& x) { print(x), print(S_end); }

    template <typename Tp, typename... Args>
    void println(Tp const& x, Args&&... xs) {
      print(x, std::forward<Args>(xs)...);
      print(S_end);
    }

    static void set_sep(char c) { S_sep = c; }
    static void set_end(char c) { S_end = c; }
  };
}  // fast::

fast::scanner cin;
fast::printer cout;

#endif  /* !defined(H_fast_io) */

#line 1 "utility/fast_io.cpp"



/**
 * @brief 高速入出力
 * @author えびちゃん
 * @see https://qiita.com/rsk0315_h4x/items/17a9cb12e0de5fd918f4
 */

#include <cstddef>
#include <cstdint>
#include <cstdio>
#include <cstring>
#include <limits>
#include <string>
#include <type_traits>
#include <utility>

#line 1 "integer/bit.cpp"



/** 
 * @brief ビット演算
 * @author えびちゃん
 */

// XXX integral promotion 関連の注意をあまりしていません

#include <climits>
#include <type_traits>

template <typename Tp>
constexpr auto countl_zero(Tp n)
  -> typename std::enable_if<std::is_unsigned<Tp>::value, int>::type
{
  using value_type = typename std::make_unsigned<Tp>::type;
  int bits = (sizeof(value_type) * CHAR_BIT);
  if (n == 0) return bits;
  int res = 0;
  for (int i = bits / 2; i > 0; i /= 2) {
    value_type mask = ((static_cast<value_type>(1) << i) - 1) << i;
    if (n & mask) n >>= i;
    else res += i;
  }
  return res;
}
template <typename Tp>
constexpr auto countl_one(Tp n)
  -> typename std::enable_if<std::is_unsigned<Tp>::value, int>::type
{
  using value_type = typename std::make_unsigned<Tp>::type;
  return countl_zero(static_cast<value_type>(~n));
}

template <typename Tp>
constexpr auto countr_zero(Tp n)
  -> typename std::enable_if<std::is_unsigned<Tp>::value, int>::type
{
  using value_type = typename std::make_unsigned<Tp>::type;
  int bits = (sizeof(value_type) * CHAR_BIT);
  if (n == 0) return bits;
  int res = 0;
  for (int i = bits / 2; i > 0; i /= 2) {
    value_type mask = ((static_cast<value_type>(1) << i) - 1);
    if (!(n & mask)) res += i, n >>= i;
  }
  return res;
}
template <typename Tp>
constexpr auto countr_one(Tp n)
  -> typename std::enable_if<std::is_unsigned<Tp>::value, int>::type
{
  using value_type = typename std::make_unsigned<Tp>::type;
  return countr_zero(static_cast<value_type>(~n));
}

constexpr unsigned long long half_mask[] = {
  0x5555555555555555uLL, 0x3333333333333333uLL, 0x0F0F0F0F0F0F0F0FuLL,
  0x00FF00FF00FF00FFuLL, 0x0000FFFF0000FFFFuLL, 0x00000000FFFFFFFFuLL
};

template <typename Tp>
constexpr auto popcount(Tp n)
  -> typename std::enable_if<std::is_unsigned<Tp>::value, int>::type
{
  int bits = static_cast<int>((sizeof n) * CHAR_BIT);
  for (int i = 0, j = 1; j < bits; ++i, j *= 2) {
    if (j <= 8) n = (n & half_mask[i]) + ((n >> j) & half_mask[i]);
    else n += n >> j;
  }
  return n & 0xFF;
}

template <typename Tp>
constexpr auto parity(Tp n)
  -> typename std::enable_if<std::is_unsigned<Tp>::value, int>::type
{ return popcount(n) & 1; }


template <typename Tp>
int clz(Tp n) { return countl_zero(static_cast<typename std::make_unsigned<Tp>::type>(n)); }
template <typename Tp>
int ctz(Tp n) { return countr_zero(static_cast<typename std::make_unsigned<Tp>::type>(n)); }

template <typename Tp>
int ilog2(Tp n) {
  return (CHAR_BIT * sizeof(Tp) - 1) - clz(static_cast<typename std::make_unsigned<Tp>::type>(n));
}
template <typename Tp>
bool is_pow2(Tp n) { return (n > 0) && ((n & (n-1)) == 0); }
template <typename Tp>
Tp floor2(Tp n) { return is_pow2(n)? n: static_cast<Tp>(1) << ilog2(n); }
template <typename Tp>
Tp ceil2(Tp n) { return is_pow2(n)? n: static_cast<Tp>(2) << ilog2(n); }

template <typename Tp>
constexpr auto reverse(Tp n)
  -> typename std::enable_if<std::is_unsigned<Tp>::value, Tp>::type
{
  int bits = static_cast<int>((sizeof n) * CHAR_BIT);
  for (int i = 0, j = 1; j < bits; ++i, j *= 2) {
    n = ((n & half_mask[i]) << j) | ((n >> j) & half_mask[i]);
  }
  return n;
}


#line 20 "utility/fast_io.cpp"

namespace fast {
  static constexpr size_t buf_size = 1 << 17;
  static constexpr size_t margin = 1;
  static char inbuf[buf_size + margin] = {};
  static __attribute__((aligned(8))) char outbuf[buf_size + margin] = {};
  static __attribute__((aligned(8))) char minibuf[32];
  static constexpr size_t int_digits = 20;  // 18446744073709551615
  static constexpr uintmax_t digit_mask = 0x3030303030303030;
  static constexpr uintmax_t first_mask = 0x00FF00FF00FF00FF;
  static constexpr uintmax_t second_mask = 0x0000FFFF0000FFFF;
  static constexpr uintmax_t third_mask = 0x00000000FFFFFFFF;
  static constexpr uintmax_t tenpow[] = {
    1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000,
    1000000000, 10000000000, 100000000000, 1000000000000, 10000000000000,
    100000000000000, 1000000000000000, 10000000000000000, 100000000000000000,
    1000000000000000000, 10000000000000000000u,
  };
  static __attribute__((aligned(8))) char inttab[40000] = {};  // 4-digit integers (10000 many)
  static char S_sep = ' ', S_end = '\n';
  template <typename Tp>
  using enable_if_integral = std::enable_if<std::is_integral<Tp>::value, Tp>;

  class scanner {
    char* pos = inbuf;
    char* endpos = inbuf + buf_size;

    void M_read_from_stdin() {
      endpos = inbuf + fread(pos, 1, buf_size, stdin);
    }
    void M_reread_from_stdin() {
      ptrdiff_t len = endpos - pos;
      if (!(inbuf + len <= pos)) return;
      memcpy(inbuf, pos, len);
      char* tmp = inbuf + len;
      endpos = tmp + fread(tmp, 1, buf_size-len, stdin);
      *endpos = 0;
      pos = inbuf;
    }

  public:
    scanner() { M_read_from_stdin(); }

    template <typename Integral,
              typename enable_if_integral<Integral>::type* = nullptr>
    void scan_parallel(Integral& x) {
      if (__builtin_expect(endpos <= pos + int_digits, 0))
        M_reread_from_stdin();
      bool ends = false;
      typename std::make_unsigned<Integral>::type y = 0;
      bool neg = false;
      if (std::is_signed<Integral>::value && *pos == '-') {
        neg = true;
        ++pos;
      }
      do {
        memcpy(minibuf, pos, 8);
        intmax_t c = *(intmax_t*)minibuf;
        intmax_t d = (c & digit_mask) ^ digit_mask;
        int skip = 8;
        int shift = 8;
        if (d) {
          int ctz = countr_zero<uintmax_t>(d);
          if (ctz == 4) break;
          c &= (1L << (ctz-5)) - 1;
          int discarded = (68-ctz) / 8;
          shift -= discarded;
          c <<= discarded * 8;
          skip -= discarded;
          ends = true;
        }
        c |= digit_mask;
        c ^= digit_mask;
        c = ((c >> 8) + c*10) & first_mask;
        c = ((c >> 16) + c*100) & second_mask;
        c = ((c >> 32) + c*10000) & third_mask;
        y = y*tenpow[shift] + c;
        pos += skip;
      } while (!ends);
      x = (neg? -y: y);
      ++pos;
    }

    template <typename Integral,
              typename enable_if_integral<Integral>::type* = nullptr>
    void scan_serial(Integral& x) {
      if (__builtin_expect(endpos <= pos + int_digits, 0))
        M_reread_from_stdin();
      bool neg = false;
      if (std::is_signed<Integral>::value && *pos == '-') {
        neg = true;
        ++pos;
      }
      typename std::make_unsigned<Integral>::type y = *pos-'0';
      while (*++pos >= '0') y = 10*y + *pos-'0';
      x = (neg? -y: y);
      ++pos;
    }

    template <typename Integral,
              typename enable_if_integral<Integral>::type* = nullptr>
    // Use scan_parallel(x) only when x may be too large (about 10^12).
    // Otherwise, even when x <= 10^9, scan_serial(x) may be faster.
    void scan(Integral& x) { scan_serial(x); }

    void scan_serial(std::string& s) {
      // until first whitespace
      s = "";
      do {
        char* startpos = pos;
        while (*pos > ' ') ++pos;
        s += std::string(startpos, pos);
        if (*pos != 0) {
          ++pos;  // skip the space
          break;
        }
        M_reread_from_stdin();
      } while (true);
    }

    void scan(std::string& s) { scan_serial(s); }

    template <typename Tp, typename... Args>
    void scan(Tp& x, Args&&... xs) {
      scan(x);
      scan(std::forward<Args>(xs)...);
    }
  };

  class printer {
    char* pos = outbuf;

    void M_flush_stdout() {
      fwrite(outbuf, 1, pos-outbuf, stdout);
      pos = outbuf;
    }

    static int S_int_digits(uintmax_t n) {
      if (n < tenpow[16]) {  // 1
        if (n < tenpow[8]) {  // 2
          if (n < tenpow[4]) {  // 3
            if (n < tenpow[2]) {  // 4
              if (n < tenpow[1]) return 1;  // 5
              return 2;  // 5
            }
            if (n < tenpow[3]) return 3;  // 4
            return 4;  // 4
          }
          if (n < tenpow[6]) {  // 4
            if (n < tenpow[5]) return 5;  // 5
            return 6;  // 5
          }
          if (n < tenpow[7]) return 7;  // 5
          return 8;  // 5
        }
        if (n < tenpow[12]) {  // 3
          if (n < tenpow[10]) {  // 4
            if (n < tenpow[9]) return 9;  // 5
            return 10;  // 5
          }
          if (n < tenpow[11]) return 11;  // 5
          return 12;  // 5
        }
        if (n < tenpow[14]) {  // 4
          if (n < tenpow[13]) return 13;  // 5
          return 14;  // 5
        }
        if (n < tenpow[15]) return 15;  // 5
        return 16;  // 5
      }
      if (n < tenpow[18]) {  // 2
        if (n < tenpow[17]) return 17;  // 3
        return 18;  // 3
      }
      return 19;  // 2
      if (n < tenpow[19]) return 19;  // 3
      return 20;  // 3
    }

    void M_precompute() {
      uintmax_t const digit1 = 0x0200000002000000;
      uintmax_t const digit2 = 0xf600fffff6010000;
      uintmax_t const digit3 = 0xfff600fffff60100;
      uintmax_t const digit4 = 0xfffff600fffff601;
      uintmax_t counter = 0x3130303030303030;
      for (int i = 0, i4 = 0; i4 < 10; ++i4, counter += digit4)
        for (int i3 = 0; i3 < 10; ++i3, counter += digit3)
          for (int i2 = 0; i2 < 10; ++i2, counter += digit2)
            for (int i1 = 0; i1 < 5; ++i1, ++i, counter += digit1)
              *((uintmax_t*)inttab + i) = counter;
    }

  public:
    printer() { M_precompute(); }
    ~printer() { M_flush_stdout(); }

    void print(char c) {
      if (__builtin_expect(pos + 1 >= outbuf + buf_size, 0)) M_flush_stdout();
      *pos++ = c;
    }

    template <size_t N>
    void print(char const(&s)[N]) {
      if (__builtin_expect(pos + N >= outbuf + buf_size, 0)) M_flush_stdout();
      memcpy(pos, s, N-1);
      pos += N-1;
    }

    void print(char const* s) {
      // FIXME: strlen や memcpy などで定数倍高速化したい
      while (*s != 0) {
        *pos++ = *s++;
        if (pos == outbuf + buf_size) M_flush_stdout();
      }
    }

    void print(std::string const& s) { print(s.data()); }

    template <typename Integral,
              typename enable_if_integral<Integral>::type* = nullptr>
    void print(Integral x) {
      if (__builtin_expect(pos + int_digits >= outbuf + buf_size, 0))
        M_flush_stdout();
      if (x == 0) {
        *pos++ = '0';
        return;
      }
      if (x < 0) {
        *pos++ = '-';
        if (__builtin_expect(x == std::numeric_limits<Integral>::min(), 0)) {
          switch (sizeof x) {
          case 2: print("32768"); return;
          case 4: print("2147483648"); return;
          case 8: print("9223372036854775808"); return;
          }
        }
        x = -x;
      }

      typename std::make_unsigned<Integral>::type y = x;
      int len = S_int_digits(y);
      pos += len;
      char* tmp = pos;
      int w = (pos - outbuf) & 3;
      if (w > len) w = len;
      for (int i = w; i > 0; --i) {
        *--tmp = y % 10 + '0';
        y /= 10;
      }
      len -= w;
      while (len >= 4) {
        tmp -= 4;
        *(unsigned*)tmp = *((unsigned*)inttab + (y % 10000));
        len -= 4;
        if (len) y /= 10000;
      }
      while (len-- > 0) {
        *--tmp = y % 10 + '0';
        y /= 10;
      }
    }

    template <typename Tp, typename... Args>
    void print(Tp const& x, Args&&... xs) {
      if (sizeof...(Args) > 0) {
        print(x);
        print(S_sep);
        print(std::forward<Args>(xs)...);
      }
    }

    template <typename Tp>
    void println(Tp const& x) { print(x), print(S_end); }

    template <typename Tp, typename... Args>
    void println(Tp const& x, Args&&... xs) {
      print(x, std::forward<Args>(xs)...);
      print(S_end);
    }

    static void set_sep(char c) { S_sep = c; }
    static void set_end(char c) { S_end = c; }
  };
}  // fast::

fast::scanner cin;
fast::printer cout;