Problem p02977 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
using namespace std;
struct fast_ios {
  fast_ios() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
  };
} fast_ios_;
#define FOR(i, begin, end) for (int i = (begin); i < (end); i++)
#define REP(i, n) FOR(i, 0, n)
#define IFOR(i, begin, end) for (int i = (end)-1; i >= (begin); i--)
#define IREP(i, n) IFOR(i, 0, n)
#define Sort(v) sort(v.begin(), v.end())
#define Reverse(v) reverse(v.begin(), v.end())
#define all(v) v.begin(), v.end()
#define SZ(v) ((int)v.size())
#define Lower_bound(v, x)                                                      \
  distance(v.begin(), lower_bound(v.begin(), v.end(), x))
#define Upper_bound(v, x)                                                      \
  distance(v.begin(), upper_bound(v.begin(), v.end(), x))
#define Max(a, b) a = max(a, b)
#define Min(a, b) a = min(a, b)
#define bit(n) (1LL << (n))
#define bit_exist(x, n) ((x >> n) & 1)
#define debug(x) cout << #x << "=" << x << endl;
#define vdebug(v)                                                              \
  cout << #v << "=" << endl;                                                   \
  REP(i_debug, v.size()) { cout << v[i_debug] << ","; }                        \
  cout << endl;
#define mdebug(m)                                                              \
  cout << #m << "=" << endl;                                                   \
  REP(i_debug, m.size()) {                                                     \
    REP(j_debug, m[i_debug].size()) { cout << m[i_debug][j_debug] << ","; }    \
    cout << endl;                                                              \
  }
#define pb push_back
#define f first
#define s second
#define int long long
#define INF 1000000000000000000
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, vector<T> &v) {
  for (int i = 0; i < v.size(); i++) {
    cout << v[i];
    if (i != v.size() - 1)
      cout << endl;
  };
  return os;
}
template <typename T> void Out(T x) { cout << x << endl; }
template <typename T1, typename T2> void Ans(bool f, T1 y, T2 n) {
  if (f)
    Out(y);
  else
    Out(n);
}

using vec = vector<int>;
using mat = vector<vec>;
using Pii = pair<int, int>;
using PiP = pair<int, Pii>;
using PPi = pair<Pii, int>;
using bools = vector<bool>;
using pairs = vector<Pii>;

// int dx[4] = {1,0,-1,0};
// int dy[4] = {0,1,0,-1};
// char d[4] = {'D','R','U','L'};

const int mod = 1000000007;
// const int mod = 998244353;
#define Add(x, y) x = (x + (y)) % mod
#define Mult(x, y) x = (x * (y)) % mod

signed main() {

  int N;
  cin >> N;
  int d;
  REP(i, 100) {
    if (N <= bit(i)) {
      d = i;
      break;
    }
  }
  if (N == bit(d)) {
    Out("No");
    return 0;
  }

  // N>=3
  pairs ans;
  ans.pb(Pii(1, 3));
  ans.pb(Pii(3, 2));
  ans.pb(Pii(2, 1 + N));
  ans.pb(Pii(1 + N, 3 + N));
  ans.pb(Pii(3 + N, 2 + N));

  for (int i = 4; i <= N; i += 2) {
    if (i + 2 == N) {
      if ((N >> 1) & 1) {
        ans.pb(Pii(i, 1));
        ans.pb(Pii(i + 1, i));
        ans.pb(Pii(i + 1 + N, i + N));
        ans.pb(Pii(i + 1 + N, 1 + N));
        ans.pb(Pii(i + 2, i));
        ans.pb(Pii(i + 2 + N, 3));
      } else {
        ans.pb(Pii(i + 2, 3));
        ans.pb(Pii(i + 1, i + 2));
        ans.pb(Pii(i + 1 + N, i + 2 + N));
        ans.pb(Pii(i + 1 + N, 3 + N));
        ans.pb(Pii(i, i + 2));
        ans.pb(Pii(i + N, 1));
        assert(false);
      }
      break;
    } else {
      ans.pb(Pii(i, 1));
      ans.pb(Pii(i + 1, i));
      ans.pb(Pii(i + 1 + N, i + N));
      ans.pb(Pii(i + 1 + N, 1 + N));
    }
  }

  Out("Yes");
  REP(i, 2 * N - 1) cout << ans[i].f << " " << ans[i].s << endl;

  return 0;
}


Fixed submission:
#include <bits/stdc++.h>
using namespace std;
struct fast_ios {
  fast_ios() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
  };
} fast_ios_;
#define FOR(i, begin, end) for (int i = (begin); i < (end); i++)
#define REP(i, n) FOR(i, 0, n)
#define IFOR(i, begin, end) for (int i = (end)-1; i >= (begin); i--)
#define IREP(i, n) IFOR(i, 0, n)
#define Sort(v) sort(v.begin(), v.end())
#define Reverse(v) reverse(v.begin(), v.end())
#define all(v) v.begin(), v.end()
#define SZ(v) ((int)v.size())
#define Lower_bound(v, x)                                                      \
  distance(v.begin(), lower_bound(v.begin(), v.end(), x))
#define Upper_bound(v, x)                                                      \
  distance(v.begin(), upper_bound(v.begin(), v.end(), x))
#define Max(a, b) a = max(a, b)
#define Min(a, b) a = min(a, b)
#define bit(n) (1LL << (n))
#define bit_exist(x, n) ((x >> n) & 1)
#define debug(x) cout << #x << "=" << x << endl;
#define vdebug(v)                                                              \
  cout << #v << "=" << endl;                                                   \
  REP(i_debug, v.size()) { cout << v[i_debug] << ","; }                        \
  cout << endl;
#define mdebug(m)                                                              \
  cout << #m << "=" << endl;                                                   \
  REP(i_debug, m.size()) {                                                     \
    REP(j_debug, m[i_debug].size()) { cout << m[i_debug][j_debug] << ","; }    \
    cout << endl;                                                              \
  }
#define pb push_back
#define f first
#define s second
#define int long long
#define INF 1000000000000000000
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, vector<T> &v) {
  for (int i = 0; i < v.size(); i++) {
    cout << v[i];
    if (i != v.size() - 1)
      cout << endl;
  };
  return os;
}
template <typename T> void Out(T x) { cout << x << endl; }
template <typename T1, typename T2> void Ans(bool f, T1 y, T2 n) {
  if (f)
    Out(y);
  else
    Out(n);
}

using vec = vector<int>;
using mat = vector<vec>;
using Pii = pair<int, int>;
using PiP = pair<int, Pii>;
using PPi = pair<Pii, int>;
using bools = vector<bool>;
using pairs = vector<Pii>;

// int dx[4] = {1,0,-1,0};
// int dy[4] = {0,1,0,-1};
// char d[4] = {'D','R','U','L'};

const int mod = 1000000007;
// const int mod = 998244353;
#define Add(x, y) x = (x + (y)) % mod
#define Mult(x, y) x = (x * (y)) % mod

signed main() {

  int N;
  cin >> N;
  int d;
  REP(i, 100) {
    if (N <= bit(i)) {
      d = i;
      break;
    }
  }
  if (N == bit(d)) {
    Out("No");
    return 0;
  }

  // N>=3
  pairs ans;
  ans.pb(Pii(1, 3));
  ans.pb(Pii(3, 2));
  ans.pb(Pii(2, 1 + N));
  ans.pb(Pii(1 + N, 3 + N));
  ans.pb(Pii(3 + N, 2 + N));

  for (int i = 4; i <= N; i += 2) {
    if (i == N) {
      ans.pb(Pii(i, bit(d - 1)));
      int r = N ^ bit(d - 1) ^ 1;
      ans.pb(Pii(i + N, r + N));
    } else {
      ans.pb(Pii(i, 1));
      ans.pb(Pii(i + 1, i));
      ans.pb(Pii(i + 1 + N, i + N));
      ans.pb(Pii(i + 1 + N, 1 + N));
    }
  }

  Out("Yes");
  REP(i, 2 * N - 1) cout << ans[i].f << " " << ans[i].s << endl;

  return 0;
}