Problem p02714 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define P pair<ll, ll>
#define FOR(I, A, B) for (ll I = ll(A); I < ll(B); ++I)
#define FORR(I, A, B) for (ll I = ll((B)-1); I >= ll(A); --I)
#define TO(x, t, f) ((x) ? (t) : (f))
#define SORT(x) (sort(x.begin(), x.end())) // 0 2 2 3 4 5 8 9
#define POSL(x, v)                                                             \
  (lower_bound(x.begin(), x.end(), v) - x.begin()) // xi>=v  x is sorted
#define POSU(x, v)                                                             \
  (upper_bound(x.begin(), x.end(), v) - x.begin()) // xi>v  x is sorted
#define NUM(x, v) (POSU(x, v) - POSL(x, v))        // x is sorted
#define REV(x) (reverse(x.begin(), x.end()))       // reverse
ll gcd_(ll a, ll b) {
  if (a % b == 0)
    return b;
  return gcd_(b, a % b);
}
ll lcm_(ll a, ll b) {
  ll c = gcd_(a, b);
  return ((a / c) * (b / c) * c);
}
#define NEXTP(x) next_permutation(x.begin(), x.end())
const ll INF = ll(1e16) + ll(7);
const ll MOD = 1000000007LL;
#define out(a) cout << fixed << setprecision((a))
// tie(a,b,c) = make_tuple(10,9,87);
#define pop_(a) __builtin_popcount((a))
ll keta(ll a) {
  ll r = 0;
  while (a) {
    a /= 10;
    r++;
  }
  return r;
}
ll ketawa(ll a) {
  ll r = 0;
  while (a) {
    r += a % 10;
    a /= 10;
  }
  return r;
}

int main() {

  int n;
  string s;
  cin >> n >> s;
  ll ans = 0;
  for (int i = 0; i < n; ++i) {
    for (int j = i + 1; j < n; j++) {
      if (s[i] == s[j])
        continue;
      for (int k = j + 1; k < n; k++) {
        if (j - k != i - j && s[k] != s[i] && s[k] != s[j])
          ans++;
      }
    }
  }
  cout << ans << endl;
}


Fixed submission:
#pragma GCC target("avx512f,avx512dq,avx512cd,avx512bw,avx512vl")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define P pair<ll, ll>
#define FOR(I, A, B) for (ll I = ll(A); I < ll(B); ++I)
#define FORR(I, A, B) for (ll I = ll((B)-1); I >= ll(A); --I)
#define TO(x, t, f) ((x) ? (t) : (f))
#define SORT(x) (sort(x.begin(), x.end())) // 0 2 2 3 4 5 8 9
#define POSL(x, v)                                                             \
  (lower_bound(x.begin(), x.end(), v) - x.begin()) // xi>=v  x is sorted
#define POSU(x, v)                                                             \
  (upper_bound(x.begin(), x.end(), v) - x.begin()) // xi>v  x is sorted
#define NUM(x, v) (POSU(x, v) - POSL(x, v))        // x is sorted
#define REV(x) (reverse(x.begin(), x.end()))       // reverse
ll gcd_(ll a, ll b) {
  if (a % b == 0)
    return b;
  return gcd_(b, a % b);
}
ll lcm_(ll a, ll b) {
  ll c = gcd_(a, b);
  return ((a / c) * (b / c) * c);
}
#define NEXTP(x) next_permutation(x.begin(), x.end())
const ll INF = ll(1e16) + ll(7);
const ll MOD = 1000000007LL;
#define out(a) cout << fixed << setprecision((a))
// tie(a,b,c) = make_tuple(10,9,87);
#define pop_(a) __builtin_popcount((a))
ll keta(ll a) {
  ll r = 0;
  while (a) {
    a /= 10;
    r++;
  }
  return r;
}
ll ketawa(ll a) {
  ll r = 0;
  while (a) {
    r += a % 10;
    a /= 10;
  }
  return r;
}

int main() {

  int n;
  string s;
  cin >> n >> s;
  ll ans = 0;
  for (int i = 0; i < n; ++i) {
    for (int j = i + 1; j < n; j++) {
      if (s[i] == s[j])
        continue;
      for (int k = j + 1; k < n; k++) {
        if (j - k != i - j && s[k] != s[i] && s[k] != s[j])
          ans++;
      }
    }
  }
  cout << ans << endl;
}