Problem p02983 (C++)

Buggy submission (status: Time Limit Exceeded):
#pragma GCC optimize("O3")

#include <algorithm>
#include <iostream>
#include <list>
#include <map>
#include <math.h>
#include <numeric>
#include <queue>
#include <set>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unordered_map>
#include <unordered_set>
using namespace std;

using QWORD = uint64_t;
using SQWORD = int64_t;
using DWORD = uint32_t;
using SDWORD = int32_t;
using WORD = uint16_t;
using SWORD = int16_t;
using BYTE = uint8_t;
using SBYTE = int8_t;
using DOUBLE = double;
using FLOAT = float;

#define MIN_SDWORD (-2147483648)
#define MAX_SDWORD (2147483647)
#define MIN_SBYTE (-128)
#define MAX_SBYTE (127)

#define MIN_SQWORD (0x8000000000000000)
#define MAX_SQWORD (0x7FFFFFFFFFFFFFFF)

#define MAX_QWORD (0xFFFFFFFFFFFFFFFF)
#define MAX_DWORD (0xFFFFFFFF)
#define MAX_WORD (0xFFFF)
#define MAX_BYTE (0xFF)

#define MAX_DOUBLE (1.0e+308)
#define DOUBLE_EPS (1.0e-12)
#define MIN_DOUBLE_N (-1.0e+308)

#define ArrayLength(a) (sizeof(a) / sizeof(a[0]))

static inline DOUBLE MAX(DOUBLE a, DOUBLE b) { return a > b ? a : b; }
static inline QWORD MAX(QWORD a, QWORD b) { return a > b ? a : b; }
static inline DWORD MAX(DWORD a, DWORD b) { return a > b ? a : b; }
static inline SDWORD MAX(SDWORD a, SDWORD b) { return a > b ? a : b; }
static inline DOUBLE MIN(DOUBLE a, DOUBLE b) { return a < b ? a : b; }
static inline QWORD MIN(QWORD a, QWORD b) { return a < b ? a : b; }
static inline DWORD MIN(DWORD a, DWORD b) { return a < b ? a : b; }
static inline SDWORD MIN(SDWORD a, SDWORD b) { return a < b ? a : b; }

#define BYTE_BITS (8)
#define WORD_BITS (16)
#define DWORD_BITS (32)
#define QWORD_BITS (64)

static inline void inputStringSpSeparated(char *pcStr) {
  char *pcCur = pcStr;
  for (;;) {
    char c = getchar();
    if (('\n' == c) || (EOF == c) || (' ' == c)) {
      break;
    }
    *pcCur = c;
    pcCur++;
  }
  *pcCur = '\0';
}

static inline void inputString(char *pcStr) {
  char *pcCur = pcStr;
  for (;;) {
    char c = getchar();
    if (('\n' == c) || (EOF == c)) {
      break;
    }
    *pcCur = c;
    pcCur++;
  }
  *pcCur = '\0';
}

static inline SQWORD inputSQWORD(void) {
  SQWORD sqNumber = 0;
  SQWORD sqMultiplier = 1;
  bool bRead = false;
  for (;;) {
    char c = getchar();
    if (!bRead) {
      if ('-' == c) {
        sqMultiplier = -1;
      }
    }
    if (('0' <= c) && (c <= '9')) {
      sqNumber *= 10LL;
      sqNumber += (SQWORD)(c - '0');
      bRead = true;
    } else {
      if (bRead) {
        return sqNumber * sqMultiplier;
      }
    }
  }
}

static inline SDWORD inputSDWORD(void) {
  SDWORD lNumber = 0;
  SDWORD lMultiplier = 1;
  bool bRead = false;
  for (;;) {
    char c = getchar();
    if (!bRead) {
      if ('-' == c) {
        lMultiplier = -1;
      }
    }
    if (('0' <= c) && (c <= '9')) {
      lNumber *= 10;
      lNumber += (c - '0');
      bRead = true;
    } else {
      if (bRead) {
        return lNumber * lMultiplier;
      }
    }
  }
}

static inline DOUBLE inputFP(void) {
  DOUBLE dInt = 0.0;
  DOUBLE dFrac = 0.0;
  DOUBLE dMultiplier = 1.0;
  DWORD dwFpCnt = 0;
  DOUBLE *pdCur = &dInt;
  bool bRead = false;
  for (;;) {
    char c = getchar();
    if (!bRead) {
      if ('-' == c) {
        dMultiplier = -1;
      }
    }
    if ('.' == c) {
      pdCur = &dFrac;
    } else if (('0' <= c) && (c <= '9')) {
      (*pdCur) *= 10;
      (*pdCur) += (DOUBLE)(c - '0');
      bRead = true;
      if (pdCur == &dFrac) {
        dwFpCnt++;
      }
    } else {
      if (bRead) {
        return dMultiplier *
               (dInt + dFrac / (pow((DOUBLE)10.0, (DOUBLE)dwFpCnt)));
      }
    }
  }
}

/**
 *  mod による操作ライブラリ
 */

#define ANS_MOD (1000000007LL)

static SQWORD addMod(SQWORD x, SQWORD y) { return (x + y) % ANS_MOD; }

static SQWORD subMod(SQWORD x, SQWORD y) { return (x - y + ANS_MOD) % ANS_MOD; }

static SQWORD mulMod(SQWORD x, SQWORD y) { return (x * y) % ANS_MOD; }

static SQWORD powMod(SQWORD x, SQWORD e) {
  SQWORD v = 1;
  for (; e; x = mulMod(x, x), e >>= 1) {
    if (e & 1) {
      v = mulMod(v, x);
    }
  }
  return v;
}

static SQWORD divMod(SQWORD x, SQWORD y) {
  return mulMod(x, powMod(y, ANS_MOD - 2));
}

static SQWORD combMod(SQWORD n, SQWORD k) {
  SQWORD v = 1;
  for (SQWORD i = 1; i <= k; i++) {
    v = divMod(mulMod(v, n - i + 1), i);
  }
  return v;
}

/*----------------------------------------------*/

int main(void) {
  SQWORD sqInput_L = inputSQWORD();
  SQWORD sqInput_R = inputSQWORD();

  SQWORD sqAns = 2019;
  for (SQWORD sqR = sqInput_L + 1; sqR <= sqInput_R; sqR++) {
    for (SQWORD sqL = sqInput_L; sqL < sqR; sqL++) {
      sqAns = min(sqAns, ((sqL * sqR) % 2019));
      if (0 == sqAns) {
        break;
      }
    }
  }
  printf("%lld\n", sqAns);

  return 0;
}

Fixed submission:
#pragma GCC optimize("O3")

#include <algorithm>
#include <iostream>
#include <list>
#include <map>
#include <math.h>
#include <numeric>
#include <queue>
#include <set>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unordered_map>
#include <unordered_set>
using namespace std;

using QWORD = uint64_t;
using SQWORD = int64_t;
using DWORD = uint32_t;
using SDWORD = int32_t;
using WORD = uint16_t;
using SWORD = int16_t;
using BYTE = uint8_t;
using SBYTE = int8_t;
using DOUBLE = double;
using FLOAT = float;

#define MIN_SDWORD (-2147483648)
#define MAX_SDWORD (2147483647)
#define MIN_SBYTE (-128)
#define MAX_SBYTE (127)

#define MIN_SQWORD (0x8000000000000000)
#define MAX_SQWORD (0x7FFFFFFFFFFFFFFF)

#define MAX_QWORD (0xFFFFFFFFFFFFFFFF)
#define MAX_DWORD (0xFFFFFFFF)
#define MAX_WORD (0xFFFF)
#define MAX_BYTE (0xFF)

#define MAX_DOUBLE (1.0e+308)
#define DOUBLE_EPS (1.0e-12)
#define MIN_DOUBLE_N (-1.0e+308)

#define ArrayLength(a) (sizeof(a) / sizeof(a[0]))

static inline DOUBLE MAX(DOUBLE a, DOUBLE b) { return a > b ? a : b; }
static inline QWORD MAX(QWORD a, QWORD b) { return a > b ? a : b; }
static inline DWORD MAX(DWORD a, DWORD b) { return a > b ? a : b; }
static inline SDWORD MAX(SDWORD a, SDWORD b) { return a > b ? a : b; }
static inline DOUBLE MIN(DOUBLE a, DOUBLE b) { return a < b ? a : b; }
static inline QWORD MIN(QWORD a, QWORD b) { return a < b ? a : b; }
static inline DWORD MIN(DWORD a, DWORD b) { return a < b ? a : b; }
static inline SDWORD MIN(SDWORD a, SDWORD b) { return a < b ? a : b; }

#define BYTE_BITS (8)
#define WORD_BITS (16)
#define DWORD_BITS (32)
#define QWORD_BITS (64)

static inline void inputStringSpSeparated(char *pcStr) {
  char *pcCur = pcStr;
  for (;;) {
    char c = getchar();
    if (('\n' == c) || (EOF == c) || (' ' == c)) {
      break;
    }
    *pcCur = c;
    pcCur++;
  }
  *pcCur = '\0';
}

static inline void inputString(char *pcStr) {
  char *pcCur = pcStr;
  for (;;) {
    char c = getchar();
    if (('\n' == c) || (EOF == c)) {
      break;
    }
    *pcCur = c;
    pcCur++;
  }
  *pcCur = '\0';
}

static inline SQWORD inputSQWORD(void) {
  SQWORD sqNumber = 0;
  SQWORD sqMultiplier = 1;
  bool bRead = false;
  for (;;) {
    char c = getchar();
    if (!bRead) {
      if ('-' == c) {
        sqMultiplier = -1;
      }
    }
    if (('0' <= c) && (c <= '9')) {
      sqNumber *= 10LL;
      sqNumber += (SQWORD)(c - '0');
      bRead = true;
    } else {
      if (bRead) {
        return sqNumber * sqMultiplier;
      }
    }
  }
}

static inline SDWORD inputSDWORD(void) {
  SDWORD lNumber = 0;
  SDWORD lMultiplier = 1;
  bool bRead = false;
  for (;;) {
    char c = getchar();
    if (!bRead) {
      if ('-' == c) {
        lMultiplier = -1;
      }
    }
    if (('0' <= c) && (c <= '9')) {
      lNumber *= 10;
      lNumber += (c - '0');
      bRead = true;
    } else {
      if (bRead) {
        return lNumber * lMultiplier;
      }
    }
  }
}

static inline DOUBLE inputFP(void) {
  DOUBLE dInt = 0.0;
  DOUBLE dFrac = 0.0;
  DOUBLE dMultiplier = 1.0;
  DWORD dwFpCnt = 0;
  DOUBLE *pdCur = &dInt;
  bool bRead = false;
  for (;;) {
    char c = getchar();
    if (!bRead) {
      if ('-' == c) {
        dMultiplier = -1;
      }
    }
    if ('.' == c) {
      pdCur = &dFrac;
    } else if (('0' <= c) && (c <= '9')) {
      (*pdCur) *= 10;
      (*pdCur) += (DOUBLE)(c - '0');
      bRead = true;
      if (pdCur == &dFrac) {
        dwFpCnt++;
      }
    } else {
      if (bRead) {
        return dMultiplier *
               (dInt + dFrac / (pow((DOUBLE)10.0, (DOUBLE)dwFpCnt)));
      }
    }
  }
}

/**
 *  mod による操作ライブラリ
 */

#define ANS_MOD (1000000007LL)

static SQWORD addMod(SQWORD x, SQWORD y) { return (x + y) % ANS_MOD; }

static SQWORD subMod(SQWORD x, SQWORD y) { return (x - y + ANS_MOD) % ANS_MOD; }

static SQWORD mulMod(SQWORD x, SQWORD y) { return (x * y) % ANS_MOD; }

static SQWORD powMod(SQWORD x, SQWORD e) {
  SQWORD v = 1;
  for (; e; x = mulMod(x, x), e >>= 1) {
    if (e & 1) {
      v = mulMod(v, x);
    }
  }
  return v;
}

static SQWORD divMod(SQWORD x, SQWORD y) {
  return mulMod(x, powMod(y, ANS_MOD - 2));
}

static SQWORD combMod(SQWORD n, SQWORD k) {
  SQWORD v = 1;
  for (SQWORD i = 1; i <= k; i++) {
    v = divMod(mulMod(v, n - i + 1), i);
  }
  return v;
}

/*----------------------------------------------*/

int main(void) {
  SQWORD sqInput_L = inputSQWORD();
  SQWORD sqInput_R = inputSQWORD();

  SQWORD sqAns = 2019;
  for (SQWORD sqR = sqInput_L + 1; sqR <= sqInput_R; sqR++) {
    for (SQWORD sqL = sqInput_L; sqL < sqR; sqL++) {
      sqAns = min(sqAns, ((sqL * sqR) % 2019));
      if (0 == sqAns) {
        printf("%lld\n", sqAns);
        return 0;
      }
    }
  }
  printf("%lld\n", sqAns);

  return 0;
}