Problem p02618 (C++)

Buggy submission (status: Runtime Error):
#define _CRT_SECURE_NO_WARNINGS
#pragma GCC target("avx")
#pragma GCC optimize("O3")
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <ctime>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <memory>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string.h>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
#define rep(i, n) for (int i = 0; i < (lint)(n); i++)
#define REP(i, n) for (int i = 1; i <= (lint)(n); i++)
#define all(V) V.begin(), V.end()
#define stackReplaceBegin(size)                                                \
  void *p = malloc(size);                                                      \
  esp_new = (lint)p + size - 1;                                                \
  void *stack_extend_memory_ = malloc(size);                                   \
  void *stack_extend_origin_memory_;                                           \
  char *stack_extend_dummy_memory_ = (char *)alloca(                           \
      (1 + (int)(((long long)stack_extend_memory_) & 127)) * 16);              \
  *stack_extend_dummy_memory_ = 0;                                             \
  asm volatile("mov %%rsp, %%rbx\nmov %%rax, %%rsp"                            \
               : "=b"(stack_extend_origin_memory_)                             \
               : "a"((char *)stack_extend_memory_ + (size)-1024));
typedef long long lint;
typedef unsigned long long ulint;
typedef std::pair<int, int> P;
constexpr int INF = INT_MAX / 2;
constexpr lint LINF = LLONG_MAX / 2;
constexpr double eps = DBL_EPSILON;
constexpr double PI = 3.141592653589793238462643383279;
lint esp_new;
template <class T>
class prique : public std::priority_queue<T, std::vector<T>, std::greater<T>> {
};
template <class T, class U> inline bool chmax(T &lhs, const U &rhs) {
  if (lhs < rhs) {
    lhs = rhs;
    return 1;
  }
  return 0;
}
template <class T, class U> inline bool chmin(T &lhs, const U &rhs) {
  if (lhs > rhs) {
    lhs = rhs;
    return 1;
  }
  return 0;
}
inline lint gcd(lint a, lint b) {
  while (b) {
    lint c = a;
    a = b;
    b = c % b;
  }
  return a;
}
inline lint lcm(lint a, lint b) { return a / gcd(a, b) * b; }
bool isprime(lint n) {
  if (n == 1)
    return false;
  for (int i = 2; i * i <= n; i++) {
    if (n % i == 0)
      return false;
  }
  return true;
}
template <typename T> T mypow(T a, unsigned int b) {
  T res(1), now(a);
  while (b) {
    if (b & 1)
      res *= now;
    b >>= 1;
    now *= now;
  }
  return res;
}
template <typename T> void printArray(std::vector<T> &vec) {
  rep(i, vec.size() - 1) std::cout << vec[i] << " ";
  std::cout << vec.back() << std::endl;
}
template <typename T> void printArray(T l, T r) {
  T rprev = r;
  rprev--;
  for (T i = l; i != rprev; i++) {
    std::cout << *i << " ";
  }
  std::cout << *rprev << std::endl;
}
int D, c[27], s[370][27], ans[370];
int curscore;
std::set<int> st[27];
std::random_device rd;
std::mt19937 mt(rd());
void change(int day, int contest) {
  int x;
  curscore -= s[day][ans[day]];
  curscore += s[day][contest];

  auto l = *--st[ans[day]].lower_bound(day);
  auto r = *st[ans[day]].upper_bound(day);

  x = day - l;
  curscore += c[ans[day]] * x * (x - 1) / 2;
  x = r - day;
  curscore += c[ans[day]] * x * (x - 1) / 2;
  x = r - l;
  curscore -= c[ans[day]] * x * (x - 1) / 2;

  l = *--st[contest].lower_bound(day);
  r = *st[contest].upper_bound(day);

  x = day - l;
  curscore -= c[contest] * x * (x - 1) / 2;
  x = r - day;
  curscore -= c[contest] * x * (x - 1) / 2;
  x = r - l;
  curscore += c[contest] * x * (x - 1) / 2;

  st[ans[day]].erase(day);
  st[contest].insert(day);
  ans[day] = contest;
}
bool check(int diff, int time) {
  if (diff < 0)
    return true;
  return mt() >= diff * (clock() - time);
}
int main() {
  freopen("sample.txt", "r", stdin);
  freopen("out.txt", "w", stdout);
  scanf("%d", &D);
  REP(i, 26) scanf("%d", c + i);
  REP(i, D) { REP(j, 26) scanf("%d", &s[i][j]); }
  REP(i, 26) {
    st[i].insert(0);
    st[i].insert(D + 1);
  }
  int last[27] = {};
  REP(i, D) {
    int max = -INF, cand;
    REP(j, 26) {
      int cnt = s[i][j];
      REP(k, 26) {
        if (j != k)
          cnt -= c[k] * (i - last[k]);
      }
      if (chmax(max, cnt))
        cand = j;
    }
    ans[i] = cand;
    st[cand].insert(i);
    last[cand] = i;
    curscore += max;
  }
  time_t time = clock();
  while ((clock() - time) <= 1.98 * CLOCKS_PER_SEC) {
    int prevscore = curscore;
    if (mt() % 3) {
      int day, contest, prevcontest;
      day = mt() % D + 1;
      contest = mt() % 26 + 1;
      prevcontest = ans[day];
      change(day, contest);
      if (!check(prevscore - curscore, time)) {
        change(day, prevcontest);
      }
    } else {
      int day = D, contest;
      while (day == D)
        day = mt() % D + 1;
      int w = mt() % (D - day) + 1;
      contest = ans[day];
      change(day, ans[day + w]);
      change(day + w, contest);
      if (!check(prevscore - curscore, time)) {
        change(day + w, ans[day]);
        change(day, contest);
      }
    }
  }
  REP(i, D) std::cout << ans[i] << std::endl;
  // std::cout<<curscore<<std::endl;
  return 0;
}

Fixed submission:
#define _CRT_SECURE_NO_WARNINGS
#pragma GCC target("avx")
#pragma GCC optimize("O3")
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <ctime>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <memory>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string.h>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
#define rep(i, n) for (int i = 0; i < (lint)(n); i++)
#define REP(i, n) for (int i = 1; i <= (lint)(n); i++)
#define all(V) V.begin(), V.end()
#define stackReplaceBegin(size)                                                \
  void *p = malloc(size);                                                      \
  esp_new = (lint)p + size - 1;                                                \
  void *stack_extend_memory_ = malloc(size);                                   \
  void *stack_extend_origin_memory_;                                           \
  char *stack_extend_dummy_memory_ = (char *)alloca(                           \
      (1 + (int)(((long long)stack_extend_memory_) & 127)) * 16);              \
  *stack_extend_dummy_memory_ = 0;                                             \
  asm volatile("mov %%rsp, %%rbx\nmov %%rax, %%rsp"                            \
               : "=b"(stack_extend_origin_memory_)                             \
               : "a"((char *)stack_extend_memory_ + (size)-1024));
typedef long long lint;
typedef unsigned long long ulint;
typedef std::pair<int, int> P;
constexpr int INF = INT_MAX / 2;
constexpr lint LINF = LLONG_MAX / 2;
constexpr double eps = DBL_EPSILON;
constexpr double PI = 3.141592653589793238462643383279;
lint esp_new;
template <class T>
class prique : public std::priority_queue<T, std::vector<T>, std::greater<T>> {
};
template <class T, class U> inline bool chmax(T &lhs, const U &rhs) {
  if (lhs < rhs) {
    lhs = rhs;
    return 1;
  }
  return 0;
}
template <class T, class U> inline bool chmin(T &lhs, const U &rhs) {
  if (lhs > rhs) {
    lhs = rhs;
    return 1;
  }
  return 0;
}
inline lint gcd(lint a, lint b) {
  while (b) {
    lint c = a;
    a = b;
    b = c % b;
  }
  return a;
}
inline lint lcm(lint a, lint b) { return a / gcd(a, b) * b; }
bool isprime(lint n) {
  if (n == 1)
    return false;
  for (int i = 2; i * i <= n; i++) {
    if (n % i == 0)
      return false;
  }
  return true;
}
template <typename T> T mypow(T a, unsigned int b) {
  T res(1), now(a);
  while (b) {
    if (b & 1)
      res *= now;
    b >>= 1;
    now *= now;
  }
  return res;
}
template <typename T> void printArray(std::vector<T> &vec) {
  rep(i, vec.size() - 1) std::cout << vec[i] << " ";
  std::cout << vec.back() << std::endl;
}
template <typename T> void printArray(T l, T r) {
  T rprev = r;
  rprev--;
  for (T i = l; i != rprev; i++) {
    std::cout << *i << " ";
  }
  std::cout << *rprev << std::endl;
}
int D, c[27], s[370][27], ans[370];
int curscore;
std::set<int> st[27];
std::random_device rd;
std::mt19937 mt(rd());
void change(int day, int contest) {
  int x;
  curscore -= s[day][ans[day]];
  curscore += s[day][contest];

  auto l = *--st[ans[day]].lower_bound(day);
  auto r = *st[ans[day]].upper_bound(day);

  x = day - l;
  curscore += c[ans[day]] * x * (x - 1) / 2;
  x = r - day;
  curscore += c[ans[day]] * x * (x - 1) / 2;
  x = r - l;
  curscore -= c[ans[day]] * x * (x - 1) / 2;

  l = *--st[contest].lower_bound(day);
  r = *st[contest].upper_bound(day);

  x = day - l;
  curscore -= c[contest] * x * (x - 1) / 2;
  x = r - day;
  curscore -= c[contest] * x * (x - 1) / 2;
  x = r - l;
  curscore += c[contest] * x * (x - 1) / 2;

  st[ans[day]].erase(day);
  st[contest].insert(day);
  ans[day] = contest;
}
bool check(int diff, int time) {
  if (diff < 0)
    return true;
  return mt() >= diff * (clock() - time);
}
int main() {
  // freopen("sample.txt","r",stdin);
  // freopen("out.txt","w",stdout);
  scanf("%d", &D);
  REP(i, 26) scanf("%d", c + i);
  REP(i, D) { REP(j, 26) scanf("%d", &s[i][j]); }
  REP(i, 26) {
    st[i].insert(0);
    st[i].insert(D + 1);
  }
  int last[27] = {};
  REP(i, D) {
    int max = -INF, cand;
    REP(j, 26) {
      int cnt = s[i][j];
      REP(k, 26) {
        if (j != k)
          cnt -= c[k] * (i - last[k]);
      }
      if (chmax(max, cnt))
        cand = j;
    }
    ans[i] = cand;
    st[cand].insert(i);
    last[cand] = i;
    curscore += max;
  }
  time_t time = clock();
  while ((clock() - time) <= 1.98 * CLOCKS_PER_SEC) {
    int prevscore = curscore;
    if (mt() % 3) {
      int day, contest, prevcontest;
      day = mt() % D + 1;
      contest = mt() % 26 + 1;
      prevcontest = ans[day];
      change(day, contest);
      if (!check(prevscore - curscore, time)) {
        change(day, prevcontest);
      }
    } else {
      int day = D, contest;
      while (day == D)
        day = mt() % D + 1;
      int w = mt() % (D - day) + 1;
      contest = ans[day];
      change(day, ans[day + w]);
      change(day + w, contest);
      if (!check(prevscore - curscore, time)) {
        change(day + w, ans[day]);
        change(day, contest);
      }
    }
  }
  REP(i, D) std::cout << ans[i] << std::endl;
  // std::cout<<curscore<<std::endl;
  return 0;
}