Language: C++

#include<iostream>
#include<set>
#include<vector>
#include<array>
#include<algorithm>
#include<chrono>

int const INF = 1e9;

uint64_t xor64(void) {
  static uint64_t x = 88172645463325252ULL;
  x = x ^ (x << 7);
  return x = x ^ (x >> 9);
}

auto b_cl = std::chrono::system_clock::now();
inline double get_time() {
  auto e_cl = std::chrono::system_clock::now();
  double msec = std::chrono::duration_cast<std::chrono::milliseconds>(e_cl - b_cl).count();
  return msec;
}

struct state {
  int score_k;
  int type;
  int last[26];
  int score;
  std::vector<state>::iterator prev;
  bool operator< (state const& rhs) const { return score_k > rhs.score_k; } // reverse order
};

int main() {
  std::cin.tie(0); std::ios::sync_with_stdio(false);
  int D; std::cin >> D;
  int c[26];
  for(auto& ci: c) std::cin >> ci;
  std::vector<std::array<int,26>> s(D);
  for(int d = 0; d < D; ++d) {
    for(auto& si: s[d]) std::cin >> si;
  }
  int const B = 840;
  int const K = 2;
  std::vector<int> t(D);
  
  std::vector<std::vector<state>> states(D+1);
  auto beam_step = [&](int d, int k) {
    auto& prev = states[d];
    auto& curr = states[d+1];
    curr.reserve(prev.size()*26);
    int dd = std::min(d+k, D-1);
    for(auto it = prev.begin(); it != prev.end(); ++it) {
      for(int T = 0; T < 26; ++T) {
        curr.push_back(*it);
        state& st = curr.back();
        st.prev = it;
        st.last[T] = d;
        st.type = T;
        st.score_k = st.score + s[d][T];
        for(int cx = 0; cx < 26; ++cx) {
          st.score_k -= c[cx]*(d+dd - 2*st.last[cx])*(dd-d+1)/2;
        }
      }
    }
    std::sort(curr.begin(), curr.end());
    if(curr.size() > B) curr.resize(B);
    for(auto& st: curr) {
      st.score += s[d][st.type];
      for(int cx = 0; cx < 26; ++cx) {
        st.score -= c[cx]*(d - st.last[cx]);
      }
    }
  };
  
  auto beam_search = [&](int k) {
    states.assign(D+1, std::vector<state>());
    states[0].emplace_back();
    states[0][0].score = 0;
    states[0][0].score_k = 0;
    std::fill_n(states[0][0].last, 26, -1);
    for(int d = 0; d < D; ++d) beam_step(d, k);
    auto it = states[D].begin();
    for(int d = D-1; d >= 0; it = it->prev, --d) {
      t[d] = it->type;
    }
  };
  beam_search(K);
  
  std::set<int> last[26];
  for(auto& li: last) li.insert(-1); // sentinel
  for(int d = 0; d < D; ++d) last[t[d]].insert(d);
  for(auto& li: last) li.insert(D); // sentinel
  
  //hill climbing
  auto sum_up = [](int d) { return d*(d-1)/2; };
  auto score = [&](int d, int i)->int {
    int res = s[d][i];
    auto it = last[i].lower_bound(d);
    int nd = *it;
    int pd = *--it;
    int diff = sum_up(d-pd) + sum_up(nd-d) - sum_up(nd-pd);
    res -= c[i]*diff;
    return res;
  };
  int lm = 0, renew = 0;
  int sc[26];
  auto one_day = [&](int d) {
    int pi = t[d];
    last[pi].erase(d);
    for(int i = 0; i < 26; ++i) sc[i] = score(d, i);
    int mi = std::max_element(sc, sc+26) - sc;
    if(mi != pi) {
      t[d] = mi;
      ans += sc[mi] - sc[pi];
      ++renew;
    }
    last[mi].insert(d);
  };
  
  // hill climbing
  int range = 25;
  for(int rep = 0;; ++rep) {
    if((xor64()>>25)%2) {
      one_day(xor64()%365);
    } else {
      // swap
      int d1 = xor64()%D, d2 = xor64()%D;
      while(d1 < d2-range || d2 < d1-range || t[d1] == t[d2]) {
          d1 = xor64()%D; d2 = xor64()%D;
      }
      int pi1 = t[d1], pi2 = t[d2];
      last[pi1].erase(d1);
      int diff = score(d1, pi2) - score(d1, pi1);
      last[pi2].insert(d1);
      last[pi2].erase(d2);
      diff += score(d2, pi1) - score(d2, pi2);
      if(diff > 0) {
        last[pi1].insert(d2);
        t[d1] = pi2;
        t[d2] = pi1;
        lm = 0;
      } else {
        last[pi2].insert(d2);
        last[pi2].erase(d1);
        last[pi1].insert(d1);
      }
    }
    if(rep%100 == 0) {
      int x = get_time();
      if(x > 1650) range = 20;
      if(x > 1800) range = 15;
      if(x > 1950) range = 10;
      if(x > 1980) break;
    }
  }
  for(auto ti: t) std::cout << ti+1 << "\n";
  return 0;
}


Compiler output:
a.cc: In lambda function:
a.cc:113:7: error: 'ans' was not declared in this scope; did you mean 'abs'?
  113 |       ans += sc[mi] - sc[pi];
      |       ^~~
      |       abs