Problem p02721 (C++) — buggy submission, verdict: Time Limit Exceeded

// #include <bits/stdc++.h>
#include <algorithm> // sort, min/max, upper/lower_bound, transform, count/copy_if
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <complex>
#include <cstring>
#include <deque>
#include <forward_list>
#include <functional>
#include <iomanip>  // setprecision
#include <iostream> // cin, cout, string
#include <iterator>
#include <list>
#include <map>
#include <numeric> // accumulate, itoa
#include <queue>   // priority_queue
#include <random>  // mt19937
#include <ratio>
#include <set> // multiset
#include <stack>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility> // pair, swap
#include <vector>

using namespace std;

// #define int long long

using i64 = int64_t;
using ll = long long;
using ld = long double;

template <typename T> using vec = vector<T>;
template <typename T> using mat = vec<vec<T>>;
template <typename T> using dic = unordered_map<string, T>;
template <typename T>
using pqg = priority_queue<T, vector<T>, greater<T>>; // dijkstra
// template<typename T, typename U> using P = pair<T, U>;
// template<typename... Args> using func = function<Args...>;
// template<typename T> using pq = priority_queue<T>;

using pii = pair<int, int>;
using ppi = pair<pii, int>;
using pip = pair<int, pii>;
using ppp = pair<pii, pii>;

using vi = vec<int>;
using mi = mat<int>; // Graph
using vp = vec<pii>;

constexpr int IINF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
// constexpr int INF = sizeof(int) == sizeof(long long) ? LINF : IINF;
constexpr long long MOD = 1e9 + 7;

#define _overload(_1, _2, _3, name, ...) name
#define _rep1(i, a, b) for (int i = (a), _##i = (b); i < _##i; ++i)
#define _rep2(i, n) _rep1(i, 0, n)
#define _rep3(n) _rep2(i, n)
#define rep(...) _overload(__VA_ARGS__, _rep1, _rep2, _rep3)(__VA_ARGS__)
#define _rrep1(i, a, b) for (int i = (b)-1, _##i = (a); i >= _##i; --i)
#define _rrep2(i, n) _rrep1(i, 0, n)
#define _rrep3(n) _rrep2(i, n)
#define rrep(...) _overload(__VA_ARGS__, _rrep1, _rrep2, _rrep3)(__VA_ARGS__)

#define each(i, a) for (auto &&i : a)
#define each2(i, a) for (const auto &i : a)

#define pb push_back
// emplace_back(*) == push_back(constructor(*))
#define eb emplace_back
#define pob pop_back
#define pf push_front
#define pof pop_front

#define np next_permutation
#define pp prev_permutation

// make_pair(A, B) == pair<T, U>(A, B)
#define mp make_pair
// mt(...) == tie(...)
#define mt make_tuple

#define ft first
#define sd second

#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define sz(a) (int)(a).size()
#define rev(a) reverse(all(a))
#define rs(a, l) (a).resize(l)

#define upper(s) transform(all(s), (s).begin(), topper)
#define lower(s) transform(all(s), (s).begin(), tolower)

#define sum(a) accumulate(all(a), 0)
#define elif else if
#define unless(a) if (!(a))
#define qt(a) #a

#define endl '\\n'
#define dec(n) fixed << setprecision(n)
#define zfl(n) setfill(‘0’) << setw(n)

template <typename T = int, T l = 0, T r = (T)MOD>
auto rnd =
    bind(uniform_int_distribution<T>(l, r),
         mt19937(chrono::steady_clock::now().time_since_epoch().count()));

template <typename T> inline constexpr T gcd(T a, T b) {
  if (a == 0 || b == 0)
    return 0;
  while (b) {
    a = a % b;
    swap(a, b);
  }
  return a;
}
template <typename T> inline constexpr T extgcd2(T a, T b, T &x, T &y) {
  x = 1;
  y = 0;
  while (b) {
    T t = a / b;
    a -= t * b;
    swap(a, b);
    x -= t * y;
    swap(x, y);
  }
  return a;
}
template <typename T> inline constexpr T lcm(T a, T b) {
  return a / gcd(a, b) * b;
}

template <typename T> inline constexpr bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T> inline constexpr bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return true;
  }
  return false;
}

template <typename A, typename B>
istream &operator>>(istream &is, pair<A, B> &p) {
  is >> p.first;
  is >> p.second;
  return is;
}
template <typename A, typename B>
ostream &operator<<(ostream &os, const pair<A, B> &p) {
  os << p.first << " " << p.second;
  return os;
}

template <typename T> istream &operator>>(istream &is, vector<T> &v) {
  for (auto &&x : v)
    is >> x;
  return is;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &v) {
  for (int i = 0; i < (int)v.size(); ++i)
    cout << v[i] << (i + 1 != (int)v.size() ? " " : "");
  return os;
}

#define debug(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg> void __f(const char *name, const Arg &arg) {
  cerr << name << " : " << arg << endl;
}
template <typename Arg, typename... Args>
void __f(const char *names, const Arg &arg, const Args &...args) {
  const char *comma = strchr(names + 1, ',');
  cerr.write(names, comma - names) << " : " << arg << " | ";
  __f(comma + 1, args...);
}

inline auto yes(const bool &c) { return c ? "yes" : "no"; }
inline auto Yes(const bool &c) { return c ? "Yes" : "No"; }
inline auto YES(const bool &c) { return c ? "YES" : "NO"; }
inline auto Possible(const bool &c) { return c ? "Possible" : "Impossible"; }
inline auto POSSIBLE(const bool &c) { return c ? "POSSIBLE" : "IMPOSSIBLE"; }

constexpr int lim = 100007; // 10^5+7

ll n, k, c;
string s;

bool check(int i) {
  if (s.at(i) == 'x')
    return false;
  int j = 0;
  int w = k;
  while (j < n) {
    if (s[j] == 'o' && i != j) {
      // cout << i << j << endl;
      j += c;
      w -= 1;
      if (w == 0)
        return false;
    }
    j++;
  }
  return true;
}

signed main() {
  cin.tie(0);
  cout.tie(0);
  ios_base::sync_with_stdio(false);

  cin >> n >> k >> c >> s;
  int i = 0;
  int j = 0;
  vec<int> l;
  vec<int> r;
  l.resize(n);
  r.resize(n);

  while (i < n && j < k) {
    if (s.at(i) == 'o') {
      l.at(j) = i;
      j += 1;
      i += c + 1;
    } else {
      i += 1;
    }
  }
  i = n - 1;
  j = k - 1;
  while (i >= 0 && j >= 0) {
    if (s.at(i) == 'o') {
      r.at(j) = i;
      j -= 1;
      i -= c + 1;
    } else {
      i -= 1;
    }
  }

  rep(k) {
    //  cout << r.at(i) << " " << l.at(i) << endl;
    if (r.at(i) == l.at(i)) {
      cout << r.at(i) + 1 << endl;
    }
  }
  return 0;
}


Error: TLE

Fixed submission:

// #include <bits/stdc++.h>
#include <algorithm> // sort, min/max, upper/lower_bound, transform, count/copy_if
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <complex>
#include <cstring>
#include <deque>
#include <forward_list>
#include <functional>
#include <iomanip>  // setprecision
#include <iostream> // cin, cout, string
#include <iterator>
#include <list>
#include <map>
#include <numeric> // accumulate, itoa
#include <queue>   // priority_queue
#include <random>  // mt19937
#include <ratio>
#include <set> // multiset
#include <stack>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility> // pair, swap
#include <vector>

using namespace std;

// #define int long long

using i64 = int64_t;
using ll = long long;
using ld = long double;

template <typename T> using vec = vector<T>;
template <typename T> using mat = vec<vec<T>>;
template <typename T> using dic = unordered_map<string, T>;
template <typename T>
using pqg = priority_queue<T, vector<T>, greater<T>>; // dijkstra
// template<typename T, typename U> using P = pair<T, U>;
// template<typename... Args> using func = function<Args...>;
// template<typename T> using pq = priority_queue<T>;

using pii = pair<int, int>;
using ppi = pair<pii, int>;
using pip = pair<int, pii>;
using ppp = pair<pii, pii>;

using vi = vec<int>;
using mi = mat<int>; // Graph
using vp = vec<pii>;

constexpr int IINF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
// constexpr int INF = sizeof(int) == sizeof(long long) ? LINF : IINF;
constexpr long long MOD = 1e9 + 7;

#define _overload(_1, _2, _3, name, ...) name
#define _rep1(i, a, b) for (int i = (a), _##i = (b); i < _##i; ++i)
#define _rep2(i, n) _rep1(i, 0, n)
#define _rep3(n) _rep2(i, n)
#define rep(...) _overload(__VA_ARGS__, _rep1, _rep2, _rep3)(__VA_ARGS__)
#define _rrep1(i, a, b) for (int i = (b)-1, _##i = (a); i >= _##i; --i)
#define _rrep2(i, n) _rrep1(i, 0, n)
#define _rrep3(n) _rrep2(i, n)
#define rrep(...) _overload(__VA_ARGS__, _rrep1, _rrep2, _rrep3)(__VA_ARGS__)

#define each(i, a) for (auto &&i : a)
#define each2(i, a) for (const auto &i : a)

#define pb push_back
// emplace_back(*) == push_back(constructor(*))
#define eb emplace_back
#define pob pop_back
#define pf push_front
#define pof pop_front

#define np next_permutation
#define pp prev_permutation

// make_pair(A, B) == pair<T, U>(A, B)
#define mp make_pair
// mt(...) == tie(...)
#define mt make_tuple

#define ft first
#define sd second

#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define sz(a) (int)(a).size()
#define rev(a) reverse(all(a))
#define rs(a, l) (a).resize(l)

#define upper(s) transform(all(s), (s).begin(), topper)
#define lower(s) transform(all(s), (s).begin(), tolower)

#define sum(a) accumulate(all(a), 0)
#define elif else if
#define unless(a) if (!(a))
#define qt(a) #a

#define endl '\\n'
#define dec(n) fixed << setprecision(n)
#define zfl(n) setfill(‘0’) << setw(n)

template <typename T = int, T l = 0, T r = (T)MOD>
auto rnd =
    bind(uniform_int_distribution<T>(l, r),
         mt19937(chrono::steady_clock::now().time_since_epoch().count()));

template <typename T> inline constexpr T gcd(T a, T b) {
  if (a == 0 || b == 0)
    return 0;
  while (b) {
    a = a % b;
    swap(a, b);
  }
  return a;
}
template <typename T> inline constexpr T extgcd2(T a, T b, T &x, T &y) {
  x = 1;
  y = 0;
  while (b) {
    T t = a / b;
    a -= t * b;
    swap(a, b);
    x -= t * y;
    swap(x, y);
  }
  return a;
}
template <typename T> inline constexpr T lcm(T a, T b) {
  return a / gcd(a, b) * b;
}

template <typename T> inline constexpr bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T> inline constexpr bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return true;
  }
  return false;
}

template <typename A, typename B>
istream &operator>>(istream &is, pair<A, B> &p) {
  is >> p.first;
  is >> p.second;
  return is;
}
template <typename A, typename B>
ostream &operator<<(ostream &os, const pair<A, B> &p) {
  os << p.first << " " << p.second;
  return os;
}

template <typename T> istream &operator>>(istream &is, vector<T> &v) {
  for (auto &&x : v)
    is >> x;
  return is;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &v) {
  for (int i = 0; i < (int)v.size(); ++i)
    cout << v[i] << (i + 1 != (int)v.size() ? " " : "");
  return os;
}

#define debug(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg> void __f(const char *name, const Arg &arg) {
  cerr << name << " : " << arg << endl;
}
template <typename Arg, typename... Args>
void __f(const char *names, const Arg &arg, const Args &...args) {
  const char *comma = strchr(names + 1, ',');
  cerr.write(names, comma - names) << " : " << arg << " | ";
  __f(comma + 1, args...);
}

inline auto yes(const bool &c) { return c ? "yes" : "no"; }
inline auto Yes(const bool &c) { return c ? "Yes" : "No"; }
inline auto YES(const bool &c) { return c ? "YES" : "NO"; }
inline auto Possible(const bool &c) { return c ? "Possible" : "Impossible"; }
inline auto POSSIBLE(const bool &c) { return c ? "POSSIBLE" : "IMPOSSIBLE"; }

constexpr int lim = 100007; // 10^5+7

ll n, k, c;
string s;

bool check(int i) {
  if (s.at(i) == 'x')
    return false;
  int j = 0;
  int w = k;
  while (j < n) {
    if (s[j] == 'o' && i != j) {
      // cout << i << j << endl;
      j += c;
      w -= 1;
      if (w == 0)
        return false;
    }
    j++;
  }
  return true;
}

signed main() {
  cin.tie(0);
  cout.tie(0);
  ios_base::sync_with_stdio(false);

  cin >> n >> k >> c >> s;
  rep(n) {
    if (check(i)) {
      cout << i + 1 << endl;
    }
  }
  return 0;
}