Problem p02721 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i, n) for (int(i) = 0; (i) < (n); (i)++)
#define rrep(i, n) for (int(i) = ((n)-1); (i) >= 0; (i)--)
#define itn int
#define miele(v) min_element(v.begin(), v.end())
#define maele(v) max_element(v.begin(), v.end())
#define SUM(v) accumulate(v.begin(), v.end(), 0LL)
#define lb(a, key) lower_bound(a.begin(), a.end(), key)
#define ub(a, key) upper_bound(a.begin(), a.end(), key)
#define COUNT(a, key) count(a.begin(), a.end(), key)
#define BITCOUNT(x) __builtin_popcount(x)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define F first
#define S second
using P = pair<int, int>;
using WeightedGraph = vector<vector<P>>;
using UnWeightedGraph = vector<vector<int>>;
const long long INF = 1LL << 60;
const int MOD = 1000000007;
void YN(bool flg) { cout << (flg ? "YES" : "NO") << '\n'; }
void Yn(bool flg) { cout << (flg ? "Yes" : "No") << '\n'; }
void yn(bool flg) { cout << (flg ? "yes" : "no") << '\n'; }
template <typename T> int getIndexOfLowerBound(vector<T> &v, T x) {
  return lower_bound(v.begin(), v.end(), x) - v.begin();
}
template <typename T> int getIndexOfUpperBound(vector<T> &v, T x) {
  return upper_bound(v.begin(), v.end(), x) - v.begin();
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
#define DUMPOUT cerr
#define repi(itr, ds) for (auto itr = ds.begin(); itr != ds.end(); itr++)
template <typename T, typename U>
istream &operator>>(istream &is, pair<T, U> &p_var) {
  is >> p_var.first >> p_var.second;
  return is;
}
template <typename T> istream &operator>>(istream &is, vector<T> &vec) {
  for (T &x : vec)
    is >> x;
  return is;
}
template <typename T> istream &operator>>(istream &is, vector<vector<T>> &df) {
  for (int i = 0; i < df.size(); i++)
    for (int j = 0; j < df[i].size(); j++)
      is >> df[i][j];
  return is;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, pair<T, U> &pair_var) {
  DUMPOUT << '{';
  os << pair_var.first;
  DUMPOUT << ',';
  os << " " << pair_var.second;
  DUMPOUT << '}';
  return os;
}
template <typename T> ostream &operator<<(ostream &os, vector<T> &vec) {
  DUMPOUT << '[';
  for (int i = 0; i < vec.size(); i++)
    os << vec[i] << (i + 1 == vec.size() ? "" : " ");
  DUMPOUT << ']';
  return os;
}
template <typename T> ostream &operator<<(ostream &os, vector<vector<T>> &df) {
  for (auto &vec : df)
    os << vec;
  return os;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, map<T, U> &map_var) {
  DUMPOUT << "{";
  repi(itr, map_var) {
    os << *itr;
    itr++;
    if (itr != map_var.end())
      DUMPOUT << ", ";
    itr--;
  }
  DUMPOUT << "}";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, set<T> &set_var) {
  DUMPOUT << "{";
  repi(itr, set_var) {
    os << *itr;
    itr++;
    if (itr != set_var.end())
      DUMPOUT << ", ";
    itr--;
  }
  DUMPOUT << "}";
  return os;
}
void print() { cout << endl; }
template <class Head, class... Tail> void print(Head &&head, Tail &&...tail) {
  cout << head;
  if (sizeof...(tail) != 0)
    cout << " ";
  print(forward<Tail>(tail)...);
}
void dump_func() { DUMPOUT << '#' << endl; }
template <typename Head, typename... Tail>
void dump_func(Head &&head, Tail &&...tail) {
  DUMPOUT << head;
  if (sizeof...(Tail) > 0)
    DUMPOUT << ", ";
  dump_func(std::move(tail)...);
}
#ifdef DEBUG_
#define DEB
#define dump(...)                                                              \
  DUMPOUT << "  " << string(#__VA_ARGS__) << ": "                              \
          << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]" << endl  \
          << "    ",                                                           \
      dump_func(__VA_ARGS__)
#else
#define DEB if (false)
#define dump(...)
#endif

signed main(void) {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n, k, c;
  cin >> n >> k >> c;
  string s;
  cin >> s;
  vector<int> l(n + 2), r(n + 2);
  l[0] = -1, r[0] = -893;
  int mae = -INF;
  int cnt = 0;
  rep(i, n) {
    if (s[i] == 'x')
      continue;
    if (abs(mae - i) > c) {
      cnt++;
      l[cnt] = i;
      mae = i;
    }
  }
  dump(l);
  mae = INF;
  cnt = k;
  rrep(i, n) {
    if (s[i] == 'x')
      continue;
    if (abs(mae - i) > c) {
      r[cnt] = i;
      cnt--;
      mae = i;
    }
  }
  dump(r);
  rep(i, k + 1) {
    if (r[i] == l[i]) {
      print(r[i] + 1);
    }
  }
}


Fixed submission:
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i, n) for (int(i) = 0; (i) < (n); (i)++)
#define rrep(i, n) for (int(i) = ((n)-1); (i) >= 0; (i)--)
#define itn int
#define miele(v) min_element(v.begin(), v.end())
#define maele(v) max_element(v.begin(), v.end())
#define SUM(v) accumulate(v.begin(), v.end(), 0LL)
#define lb(a, key) lower_bound(a.begin(), a.end(), key)
#define ub(a, key) upper_bound(a.begin(), a.end(), key)
#define COUNT(a, key) count(a.begin(), a.end(), key)
#define BITCOUNT(x) __builtin_popcount(x)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define F first
#define S second
using P = pair<int, int>;
using WeightedGraph = vector<vector<P>>;
using UnWeightedGraph = vector<vector<int>>;
const long long INF = 1LL << 60;
const int MOD = 1000000007;
void YN(bool flg) { cout << (flg ? "YES" : "NO") << '\n'; }
void Yn(bool flg) { cout << (flg ? "Yes" : "No") << '\n'; }
void yn(bool flg) { cout << (flg ? "yes" : "no") << '\n'; }
template <typename T> int getIndexOfLowerBound(vector<T> &v, T x) {
  return lower_bound(v.begin(), v.end(), x) - v.begin();
}
template <typename T> int getIndexOfUpperBound(vector<T> &v, T x) {
  return upper_bound(v.begin(), v.end(), x) - v.begin();
}
template <class T> inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T> inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
#define DUMPOUT cerr
#define repi(itr, ds) for (auto itr = ds.begin(); itr != ds.end(); itr++)
template <typename T, typename U>
istream &operator>>(istream &is, pair<T, U> &p_var) {
  is >> p_var.first >> p_var.second;
  return is;
}
template <typename T> istream &operator>>(istream &is, vector<T> &vec) {
  for (T &x : vec)
    is >> x;
  return is;
}
template <typename T> istream &operator>>(istream &is, vector<vector<T>> &df) {
  for (int i = 0; i < df.size(); i++)
    for (int j = 0; j < df[i].size(); j++)
      is >> df[i][j];
  return is;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, pair<T, U> &pair_var) {
  DUMPOUT << '{';
  os << pair_var.first;
  DUMPOUT << ',';
  os << " " << pair_var.second;
  DUMPOUT << '}';
  return os;
}
template <typename T> ostream &operator<<(ostream &os, vector<T> &vec) {
  DUMPOUT << '[';
  for (int i = 0; i < vec.size(); i++)
    os << vec[i] << (i + 1 == vec.size() ? "" : " ");
  DUMPOUT << ']';
  return os;
}
template <typename T> ostream &operator<<(ostream &os, vector<vector<T>> &df) {
  for (auto &vec : df)
    os << vec;
  return os;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, map<T, U> &map_var) {
  DUMPOUT << "{";
  repi(itr, map_var) {
    os << *itr;
    itr++;
    if (itr != map_var.end())
      DUMPOUT << ", ";
    itr--;
  }
  DUMPOUT << "}";
  return os;
}
template <typename T> ostream &operator<<(ostream &os, set<T> &set_var) {
  DUMPOUT << "{";
  repi(itr, set_var) {
    os << *itr;
    itr++;
    if (itr != set_var.end())
      DUMPOUT << ", ";
    itr--;
  }
  DUMPOUT << "}";
  return os;
}
void print() { cout << endl; }
template <class Head, class... Tail> void print(Head &&head, Tail &&...tail) {
  cout << head;
  if (sizeof...(tail) != 0)
    cout << " ";
  print(forward<Tail>(tail)...);
}
void dump_func() { DUMPOUT << '#' << endl; }
template <typename Head, typename... Tail>
void dump_func(Head &&head, Tail &&...tail) {
  DUMPOUT << head;
  if (sizeof...(Tail) > 0)
    DUMPOUT << ", ";
  dump_func(std::move(tail)...);
}
#ifdef DEBUG_
#define DEB
#define dump(...)                                                              \
  DUMPOUT << "  " << string(#__VA_ARGS__) << ": "                              \
          << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]" << endl  \
          << "    ",                                                           \
      dump_func(__VA_ARGS__)
#else
#define DEB if (false)
#define dump(...)
#endif

signed main(void) {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n, k, c;
  cin >> n >> k >> c;
  string s;
  cin >> s;
  vector<int> l(n + 2), r(n + 2);
  l[0] = -1, r[0] = -893;
  int mae = -INF;
  int cnt = 0;
  rep(i, n) {
    if (s[i] == 'x')
      continue;
    if (abs(mae - i) > c) {
      cnt++;
      l[cnt] = i;
      mae = i;
    }
  }
  dump(l);
  mae = INF;
  cnt = k;
  rrep(i, n) {
    if (s[i] == 'x')
      continue;
    if (abs(mae - i) > c) {
      if (cnt == -1)
        break;
      r[cnt] = i;
      cnt--;
      mae = i;
    }
  }
  dump(r);
  rep(i, k + 1) {
    if (r[i] == l[i]) {
      print(r[i] + 1);
    }
  }
}