Problem p02726 (C++)

Buggy submission (status: Time Limit Exceeded):
// Keep Working Hard
//  I__Like__Food
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define rep(i, a, b) for (int i = a; i <= b; i++)
#define rep2(i, a, b) for (int i = a; i >= b; i--)
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
using namespace std;
using namespace __gnu_pbds;
#define IOS                                                                    \
  ios::sync_with_stdio(0);                                                     \
  cin.tie(0);                                                                  \
  cout.tie(0);
#define endl "\n"
#define int long long
#define all(v) v.begin(), v.end()
#define PB push_back
#define MP make_pair
#define double long double
#define trace1(x) cerr << #x << ": " << x << endl
#define trace2(x, y) cerr << #x << ": " << x << " | " << #y << ": " << y << endl
#define trace3(x, y, z)                                                        \
  cerr << #x << ":" << x << " | " << #y << ": " << y << " | " << #z << ": "    \
       << z << endl
#define trace4(a, b, c, d)                                                     \
  cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": "   \
       << c << " | " << #d << ": " << d << endl
#define trace5(a, b, c, d, e)                                                  \
  cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": "   \
       << c << " | " << #d << ": " << d << " | " << #e << ": " << e << endl
#define trace6(a, b, c, d, e, f)                                               \
  cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": "   \
       << c << " | " << #d << ": " << d << " | " << #e << ": " << e << " | "   \
       << #f << ": " << f << endl
#define cases                                                                  \
  int testcases;                                                               \
  cin >> testcases;                                                            \
  while (testcases--)
const int mod = 1e9 + 7;
const int N = 200005;
const int INF = 1e16;
const double PI = acos(-1);

vector<int> adj[N];
int bvis[N];

int dist[N];

void bfs(int u) {

  queue<int> q;
  q.push(u);
  dist[u] = 0;
  while (q.size()) {
    u = q.front(), q.pop();
    for (int &v : adj[u]) {
      if (!bvis[v]) {
        dist[v] = dist[u] + 1;
        bvis[v] = 1;
        q.push(v);
      }
    }
  }
}

int ans[N];

int32_t main() {

  IOS

      int n,
      x, y;
  cin >> n >> x >> y;

  for (int i = 1; i <= n - 1; i++) {
    adj[i].PB(i + 1);
    adj[i + 1].PB(i);
  }

  adj[x].PB(y);
  adj[y].PB(x);

  set<pair<int, int>> s;
  map<int, int> mp;

  for (int i = 1; i <= n; i++) {
    bfs(i);
    dist[i] = 0;
    for (int j = 1; j <= n; j++) {
      int xx = i;
      int yy = j;
      if (xx > yy)
        swap(xx, yy);
      if (!s.count({xx, yy})) {
        mp[dist[yy]]++;
        s.insert({xx, yy});
      }
    }

    for (int j = 1; j <= n; j++) {
      bvis[j] = false;
      dist[j] = 0;
    }
  }

  for (auto i : mp) {

    // trace2(i.first,i.second);
    if (i.first >= 1 and i.first <= n - 1) {
      ans[i.first] = i.second;
    }
  }

  for (int i = 1; i <= n - 1; i++)
    cout << ans[i] << endl;

  // bfs(4);

  // for(int i = 1; i <= n; i++)
  // {
  //   cout << dist[i] << endl;
  // }

  return 0;
}

Fixed submission:
// Keep Working Hard
//  I__Like__Food
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define rep(i, a, b) for (int i = a; i <= b; i++)
#define rep2(i, a, b) for (int i = a; i >= b; i--)
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
using namespace std;
using namespace __gnu_pbds;
#define IOS                                                                    \
  ios::sync_with_stdio(0);                                                     \
  cin.tie(0);                                                                  \
  cout.tie(0);
#define endl "\n"
#define int long long
#define all(v) v.begin(), v.end()
#define PB push_back
#define MP make_pair
#define double long double
#define trace1(x) cerr << #x << ": " << x << endl
#define trace2(x, y) cerr << #x << ": " << x << " | " << #y << ": " << y << endl
#define trace3(x, y, z)                                                        \
  cerr << #x << ":" << x << " | " << #y << ": " << y << " | " << #z << ": "    \
       << z << endl
#define trace4(a, b, c, d)                                                     \
  cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": "   \
       << c << " | " << #d << ": " << d << endl
#define trace5(a, b, c, d, e)                                                  \
  cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": "   \
       << c << " | " << #d << ": " << d << " | " << #e << ": " << e << endl
#define trace6(a, b, c, d, e, f)                                               \
  cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": "   \
       << c << " | " << #d << ": " << d << " | " << #e << ": " << e << " | "   \
       << #f << ": " << f << endl
#define cases                                                                  \
  int testcases;                                                               \
  cin >> testcases;                                                            \
  while (testcases--)
const int mod = 1e9 + 7;
const int N = 200005;
const int INF = 1e16;
const double PI = acos(-1);

vector<int> adj[N];
int bvis[N];

int dist[N];

void bfs(int u) {

  queue<int> q;
  q.push(u);
  dist[u] = 0;
  while (q.size()) {
    u = q.front(), q.pop();
    for (int &v : adj[u]) {
      if (!bvis[v]) {
        dist[v] = dist[u] + 1;
        bvis[v] = 1;
        q.push(v);
      }
    }
  }
}

int ans[N];

int32_t main() {

  IOS

      int n,
      x, y;
  cin >> n >> x >> y;

  for (int i = 1; i <= n - 1; i++) {
    adj[i].PB(i + 1);
    adj[i + 1].PB(i);
  }

  adj[x].PB(y);
  adj[y].PB(x);

  set<pair<int, int>> s;
  map<int, int> mp;

  for (int i = 1; i <= n; i++) {
    bfs(i);
    dist[i] = 0;
    for (int j = 1; j <= n; j++) {
      int xx = i;
      int yy = j;
      if (xx > yy)
        swap(xx, yy);
      if (!s.count({xx, yy})) {
        mp[dist[yy]]++;
        s.insert({xx, yy});
      }
      bvis[j] = false;
      dist[j] = 0;
    }
  }

  for (auto i : mp) {

    // trace2(i.first,i.second);
    if (i.first >= 1 and i.first <= n - 1) {
      ans[i.first] = i.second;
    }
  }

  for (int i = 1; i <= n - 1; i++)
    cout << ans[i] << endl;

  // bfs(4);

  // for(int i = 1; i <= n; i++)
  // {
  //   cout << dist[i] << endl;
  // }

  return 0;
}