Problem p01133 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <complex>
#include <cstdio>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
using namespace std;

// common

typedef int i32;
typedef long long i64, ll;
typedef long double ld;

#define BR "\\n"
#define ALL(c) (c).begin(), (c).end()
#define REP(i, n) for (int i = 0; i < (int)(n); ++i)
#define FOR(i, l, r) for (int i = (int)l; i < (int)(r); ++i)
#define EACH(it, o) for (auto it = (o).begin(); it != (o).end(); ++it)
#define IN(l, v, r) ((l) <= (v) && (v) < (r))

// config
// #define NDEBUG
// #define INF 1<<30
// #define EPS 1e-8
// const ll MOD =100000007;

// debug
#ifdef NDEBUG
#define DUMP(x)
#define DUMPLN(x)
#define DEBUG(x)
#define DEBUGLN(x)
#define LINE()
#define LINELN()
#define CHECK(exp, act)
#define STOP(e)
#else
#define DUMP(x) cerr << #x << " = " << (x)
#define DUMPLN(x) DUMP(x) << endl
#define DEBUG(x) DUMP(x) << LINE() << " " << __FILE__
#define DEBUGLN(x) DEBUG(x) << endl
#define LINE() cerr << " (L" << __LINE__ << ")"
#define LINELN() LINE() << endl
#define CHECK(exp, act)                                                        \\
  if (exp != act) {                                                            \\
    DUMPLN(exp);                                                               \\
    DEBUGLN(act);                                                              \\
  }
#define STOP(e)                                                                \\
  CHECK(e, true);                                                              \\
  if (!(e))                                                                    \\
    exit(1);
#endif

template <class T> inline string toString(const vector<T> &x) {
  stringstream ss;
  REP(i, x.size()) {
    if (i != 0)
      ss << " ";
    ss << x[i];
  }
  return ss.str();
}

template <class T> inline string toString(const vector<vector<T>> &map) {
  stringstream ss;
  REP(i, map.size()) {
    if (i != 0)
      ss << BR;
    ss << toString(map[i]);
  }
  return ss.str();
}
template <class K, class V> string toString(map<K, V> &x) {
  string res;
  stringstream ss;
  for (auto &p : x)
    ss << p.first << ":" << p.second << " ";
  return ss.str();
}

string BITtoString(int bit) {
  stringstream ss;
  while (bit != 0) {
    ss << (bit % 2);
    bit /= 2;
  }
  string res = ss.str();
  reverse(ALL(res));
  return res;
}

template <typename T, typename V> inline T pmod(T v, V MOD) {
  return (v % MOD + MOD) % MOD;
}
#define nextInt(n) scanf("%d", &n)
#define defInt(n)                                                              \\
  int n;                                                                       \\
  nextInt(n)
#define nextLong(n) scanf("%lld", &n)
#define defLong(n)                                                             \\
  ll n;                                                                        \\
  nextLong(n)
#define nextDouble(n) scanf("%lf", &n)

double INF = 1e16;
double EPS = 1e-9;
class Main {
public:
  int n;
  double hx, hy, dx, dy;
  vector<double> cx, cy;
  vector<vector<double>> ds;

  bool dfs(int v, int bit, double t) {
    if (bit == (1 << n) - 1)
      return true;
    // cut
    REP(i, n) if (!((bit >> i) & 1)) {
      double d = v != -1 ? hypot(cx[i] - cx[v], cy[i] - cy[v])
                         : hypot(cx[i] - hx, cy[i] - hy);
      if (!(d + t < hypot(cx[i] - dx, cy[i] - dy)))
        return false;
    }

    REP(i, n) if (!((bit >> i) & 1)) {
      double d = v != -1 ? hypot(cx[i] - cx[v], cy[i] - cy[v])
                         : hypot(cx[i] - hx, cy[i] - hy);
      if (d + t < hypot(cx[i] - dx, cy[i] - dy))
        if (dfs(i, bit | 1 << i, d + t))
          return true;
    }
    return false;
  }

  void run() {
    // ifstream cin("D2");
    //		ofstream cout( "D2.out" );

    while (true) {
      cin >> n >> hx >> hy >> dx >> dy;
      if (n == 0)
        break;
      cx = vector<double>(n);
      cy = vector<double>(n);
      REP(i, n) cin >> cx[i] >> cy[i];

      bool ok = false;
      ok = dfs(-1, 0, 0);
      cout << (ok ? "YES" : "NO") << endl;
    }
  }
};
int main() {
  cout << fixed << setprecision(15);
  ios::sync_with_stdio(false);
  Main().run();
  return 0;
}

Error: TLE

Fixed submission:

#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <complex>
#include <cstdio>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
using namespace std;

// common

typedef int i32;
typedef long long i64, ll;
typedef long double ld;

#define BR "\\n"
#define ALL(c) (c).begin(), (c).end()
#define REP(i, n) for (int i = 0; i < (int)(n); ++i)
#define FOR(i, l, r) for (int i = (int)l; i < (int)(r); ++i)
#define EACH(it, o) for (auto it = (o).begin(); it != (o).end(); ++it)
#define IN(l, v, r) ((l) <= (v) && (v) < (r))

// config
// #define NDEBUG
// #define INF 1<<30
// #define EPS 1e-8
// const ll MOD =100000007;

// debug
#ifdef NDEBUG
#define DUMP(x)
#define DUMPLN(x)
#define DEBUG(x)
#define DEBUGLN(x)
#define LINE()
#define LINELN()
#define CHECK(exp, act)
#define STOP(e)
#else
#define DUMP(x) cerr << #x << " = " << (x)
#define DUMPLN(x) DUMP(x) << endl
#define DEBUG(x) DUMP(x) << LINE() << " " << __FILE__
#define DEBUGLN(x) DEBUG(x) << endl
#define LINE() cerr << " (L" << __LINE__ << ")"
#define LINELN() LINE() << endl
#define CHECK(exp, act)                                                        \\
  if (exp != act) {                                                            \\
    DUMPLN(exp);                                                               \\
    DEBUGLN(act);                                                              \\
  }
#define STOP(e)                                                                \\
  CHECK(e, true);                                                              \\
  if (!(e))                                                                    \\
    exit(1);
#endif

template <class T> inline string toString(const vector<T> &x) {
  stringstream ss;
  REP(i, x.size()) {
    if (i != 0)
      ss << " ";
    ss << x[i];
  }
  return ss.str();
}

template <class T> inline string toString(const vector<vector<T>> &map) {
  stringstream ss;
  REP(i, map.size()) {
    if (i != 0)
      ss << BR;
    ss << toString(map[i]);
  }
  return ss.str();
}
template <class K, class V> string toString(map<K, V> &x) {
  string res;
  stringstream ss;
  for (auto &p : x)
    ss << p.first << ":" << p.second << " ";
  return ss.str();
}

string BITtoString(int bit) {
  stringstream ss;
  while (bit != 0) {
    ss << (bit % 2);
    bit /= 2;
  }
  string res = ss.str();
  reverse(ALL(res));
  return res;
}

template <typename T, typename V> inline T pmod(T v, V MOD) {
  return (v % MOD + MOD) % MOD;
}
#define nextInt(n) scanf("%d", &n)
#define defInt(n)                                                              \\
  int n;                                                                       \\
  nextInt(n)
#define nextLong(n) scanf("%lld", &n)
#define defLong(n)                                                             \\
  ll n;                                                                        \\
  nextLong(n)
#define nextDouble(n) scanf("%lf", &n)

double INF = 1e16;
double EPS = 1e-9;
class Main {
public:
  int n;
  double hx, hy, dx, dy;
  vector<double> cx, cy;
  vector<vector<double>> ds;

  bool dfs(int v, int bit, double t) {
    if (bit == (1 << n) - 1)
      return true;
    // cut
    REP(i, n) if (!((bit >> i) & 1)) {
      double d = v != -1 ? hypot(cx[i] - cx[v], cy[i] - cy[v])
                         : hypot(cx[i] - hx, cy[i] - hy);
      if (!(d + t < hypot(cx[i] - dx, cy[i] - dy)))
        return false;
    }

    bool ok = false;
    REP(i, n) if (!((bit >> i) & 1)) {
      double d = v != -1 ? hypot(cx[i] - cx[v], cy[i] - cy[v])
                         : hypot(cx[i] - hx, cy[i] - hy);
      if (d + t < hypot(cx[i] - dx, cy[i] - dy))
        ok |= dfs(i, bit | 1 << i, d + t);
    }
    return ok;
  }

  void run() {
    // ifstream cin("D2");
    //		ofstream cout( "D2.out" );

    while (true) {
      cin >> n >> hx >> hy >> dx >> dy;
      if (n == 0)
        break;
      cx = vector<double>(n);
      cy = vector<double>(n);
      REP(i, n) cin >> cx[i] >> cy[i];

      bool ok = false;
      ok = dfs(-1, 0, 0);
      cout << (ok ? "YES" : "NO") << endl;
    }
  }
};
int main() {
  cout << fixed << setprecision(15);
  ios::sync_with_stdio(false);
  Main().run();
  return 0;
}