Problem p03165 (C++)

Buggy submission (status: Runtime Error):
#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; }
static inline DOUBLE ABS(DOUBLE a) { return 0 < a ? a : -a; };

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

#define ANS_MOD (1000000007)

static const DOUBLE d_PI = 3.14159265358979323846;
// static const DOUBLE d_PI = M_PI;

static inline bool DoubleIsEqual(DOUBLE a, DOUBLE b) {
  return ABS(a - b) < DOUBLE_EPS;
}

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 (1000000007)

class MODINT {
  static SQWORD MOD;
  SQWORD m_x;

public:
  MODINT(SQWORD val) { m_x = (val % MOD + MOD) % MOD; };
  MODINT() { m_x = 0; }
  static void Init(SQWORD sqMod) { MOD = sqMod; }

  MODINT &operator+=(const MODINT a) {
    m_x = (m_x + a.m_x) % MOD;
    return *this;
  };
  MODINT &operator-=(const MODINT a) {
    m_x = (m_x - a.m_x + MOD) % MOD;
    return *this;
  };
  MODINT &operator*=(const MODINT a) {
    m_x = (m_x * a.m_x) % MOD;
    return *this;
  };
  MODINT pow(SQWORD t) const {
    if (!t)
      return 1;
    MODINT a = pow(t >> 1);
    a *= a;
    if (t & 1)
      a *= *this;
    return a;
  }
  MODINT operator+(const MODINT a) const {
    MODINT res(*this);
    return (res += a);
  }
  MODINT operator-(const MODINT a) const {
    MODINT res(*this);
    return (res -= a);
  }
  MODINT operator*(const MODINT a) const {
    MODINT res(*this);
    return (res *= a);
  }
  MODINT operator/(const MODINT a) const {
    MODINT res(*this);
    return (res /= a);
  }

  /* 逆元 */
  MODINT inv() const { return pow(MOD - 2); }

  /* 除算 */
  MODINT &operator/=(const MODINT a) { return (*this) *= a.inv(); }

  /* 整数版 */
  MODINT &operator+=(const SQWORD a) {
    *this += MODINT(a);
    return *this;
  };
  MODINT &operator-=(const SQWORD a) {
    *this -= MODINT(a);
    return *this;
  };
  MODINT &operator*=(const SQWORD a) {
    *this *= MODINT(a);
    return *this;
  };
  MODINT &operator/=(const SQWORD a) {
    *this /= MODINT(a);
    return *this;
  };

  SQWORD getVal() { return m_x; };
};
SQWORD MODINT::MOD = ANS_MOD;

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

#define N_MAX_STRING (3000)

static SQWORD s_aasqDpTbl[N_MAX_STRING + 1][N_MAX_STRING + 1];
static SQWORD s_aasqPrevTbl[N_MAX_STRING + 1][N_MAX_STRING + 1];

int main(void) {
  string strS, strT;

  cin >> strS;
  cin >> strT;

  SQWORD sqLenS = strS.size();
  SQWORD sqLenT = strT.size();

  /**
   *  dp[i][j]: S の i文字目・T の j文字目までで一致している文字数
   */
  for (SQWORD sqI = 0; sqI <= sqLenS; sqI++) {
    for (SQWORD sqJ = 0; sqJ <= sqLenT; sqJ++) {
      if (strS[sqI] == strT[sqJ]) {
        /* 一致 */
        s_aasqDpTbl[sqI + 1][sqJ + 1] = s_aasqDpTbl[sqI][sqJ] + 1;
        s_aasqPrevTbl[sqI + 1][sqJ + 1] = ((sqI << WORD_BITS) | sqJ);
      } else {
        /* 不一致 */
        if (s_aasqDpTbl[sqI + 1][sqJ] < s_aasqDpTbl[sqI][sqJ]) {
          s_aasqDpTbl[sqI + 1][sqJ] = s_aasqDpTbl[sqI][sqJ];
          s_aasqPrevTbl[sqI + 1][sqJ] = ((sqI << WORD_BITS) | sqJ);
        }
        if (s_aasqDpTbl[sqI][sqJ + 1] < s_aasqDpTbl[sqI][sqJ]) {
          s_aasqDpTbl[sqI][sqJ + 1] = s_aasqDpTbl[sqI][sqJ];
          s_aasqPrevTbl[sqI][sqJ + 1] = ((sqI << WORD_BITS) | sqJ);
        }
      }
    }
  }

  SQWORD sqPosS = sqLenS;
  SQWORD sqPosT = sqLenT;
  string strAns;
  while ((0 < sqPosS) && (0 < sqPosT)) {
    SQWORD sqPrevPosS = s_aasqPrevTbl[sqPosS][sqPosT] >> WORD_BITS;
    SQWORD sqPrevPosT =
        (s_aasqPrevTbl[sqPosS][sqPosT] << (QWORD_BITS - WORD_BITS)) >>
        (QWORD_BITS - WORD_BITS);
    sqPosS = sqPrevPosS;
    sqPosT = sqPrevPosT;
    if (strS[sqPosS] == strT[sqPosT]) {
      strAns += strS[sqPosS];
    }
    //        printf("%lld %lld\n", sqPrevPosS, sqPrevPosT);
  }
  if (0 < strAns.size()) {
    reverse(strAns.begin(), strAns.end());
  }
  printf("%s\n", strAns.c_str());

  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; }
static inline DOUBLE ABS(DOUBLE a) { return 0 < a ? a : -a; };

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

#define ANS_MOD (1000000007)

static const DOUBLE d_PI = 3.14159265358979323846;
// static const DOUBLE d_PI = M_PI;

static inline bool DoubleIsEqual(DOUBLE a, DOUBLE b) {
  return ABS(a - b) < DOUBLE_EPS;
}

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 (1000000007)

class MODINT {
  static SQWORD MOD;
  SQWORD m_x;

public:
  MODINT(SQWORD val) { m_x = (val % MOD + MOD) % MOD; };
  MODINT() { m_x = 0; }
  static void Init(SQWORD sqMod) { MOD = sqMod; }

  MODINT &operator+=(const MODINT a) {
    m_x = (m_x + a.m_x) % MOD;
    return *this;
  };
  MODINT &operator-=(const MODINT a) {
    m_x = (m_x - a.m_x + MOD) % MOD;
    return *this;
  };
  MODINT &operator*=(const MODINT a) {
    m_x = (m_x * a.m_x) % MOD;
    return *this;
  };
  MODINT pow(SQWORD t) const {
    if (!t)
      return 1;
    MODINT a = pow(t >> 1);
    a *= a;
    if (t & 1)
      a *= *this;
    return a;
  }
  MODINT operator+(const MODINT a) const {
    MODINT res(*this);
    return (res += a);
  }
  MODINT operator-(const MODINT a) const {
    MODINT res(*this);
    return (res -= a);
  }
  MODINT operator*(const MODINT a) const {
    MODINT res(*this);
    return (res *= a);
  }
  MODINT operator/(const MODINT a) const {
    MODINT res(*this);
    return (res /= a);
  }

  /* 逆元 */
  MODINT inv() const { return pow(MOD - 2); }

  /* 除算 */
  MODINT &operator/=(const MODINT a) { return (*this) *= a.inv(); }

  /* 整数版 */
  MODINT &operator+=(const SQWORD a) {
    *this += MODINT(a);
    return *this;
  };
  MODINT &operator-=(const SQWORD a) {
    *this -= MODINT(a);
    return *this;
  };
  MODINT &operator*=(const SQWORD a) {
    *this *= MODINT(a);
    return *this;
  };
  MODINT &operator/=(const SQWORD a) {
    *this /= MODINT(a);
    return *this;
  };

  SQWORD getVal() { return m_x; };
};
SQWORD MODINT::MOD = ANS_MOD;

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

#define N_MAX_STRING (3000)

static SQWORD s_aasqDpTbl[N_MAX_STRING + 2][N_MAX_STRING + 2];
static SQWORD s_aasqPrevTbl[N_MAX_STRING + 2][N_MAX_STRING + 2];

int main(void) {
  string strS, strT;

  cin >> strS;
  cin >> strT;

  SQWORD sqLenS = strS.size();
  SQWORD sqLenT = strT.size();

  /**
   *  dp[i][j]: S の i文字目・T の j文字目までで一致している文字数
   */
  for (SQWORD sqI = 0; sqI <= sqLenS; sqI++) {
    for (SQWORD sqJ = 0; sqJ <= sqLenT; sqJ++) {
      if (strS[sqI] == strT[sqJ]) {
        /* 一致 */
        s_aasqDpTbl[sqI + 1][sqJ + 1] = s_aasqDpTbl[sqI][sqJ] + 1;
        s_aasqPrevTbl[sqI + 1][sqJ + 1] = ((sqI << WORD_BITS) | sqJ);
      } else {
        /* 不一致 */
        if (s_aasqDpTbl[sqI + 1][sqJ] < s_aasqDpTbl[sqI][sqJ]) {
          s_aasqDpTbl[sqI + 1][sqJ] = s_aasqDpTbl[sqI][sqJ];
          s_aasqPrevTbl[sqI + 1][sqJ] = ((sqI << WORD_BITS) | sqJ);
        }
        if (s_aasqDpTbl[sqI][sqJ + 1] < s_aasqDpTbl[sqI][sqJ]) {
          s_aasqDpTbl[sqI][sqJ + 1] = s_aasqDpTbl[sqI][sqJ];
          s_aasqPrevTbl[sqI][sqJ + 1] = ((sqI << WORD_BITS) | sqJ);
        }
      }
    }
  }

  SQWORD sqPosS = sqLenS;
  SQWORD sqPosT = sqLenT;
  string strAns;
  while ((0 < sqPosS) && (0 < sqPosT)) {
    SQWORD sqPrevPosS = s_aasqPrevTbl[sqPosS][sqPosT] >> WORD_BITS;
    SQWORD sqPrevPosT =
        (s_aasqPrevTbl[sqPosS][sqPosT] << (QWORD_BITS - WORD_BITS)) >>
        (QWORD_BITS - WORD_BITS);
    sqPosS = sqPrevPosS;
    sqPosT = sqPrevPosT;
    if (strS[sqPosS] == strT[sqPosT]) {
      strAns += strS[sqPosS];
    }
    //        printf("%lld %lld\n", sqPrevPosS, sqPrevPosT);
  }
  if (0 < strAns.size()) {
    reverse(strAns.begin(), strAns.end());
  }
  printf("%s\n", strAns.c_str());

  return 0;
}