Problem p01350 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>

using namespace std;

inline int toInt(string s) {
  int v;
  istringstream sin(s);
  sin >> v;
  return v;
}
template <class T> inline string toString(T x) {
  ostringstream sout;
  sout << x;
  return sout.str();
}
template <class T> inline T sqr(T x) { return x * x; }

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<string> vs;
typedef pair<int, int> pii;
typedef long long ll;

#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define pb push_back
#define mp make_pair
#define each(i, c)                                                             \\
  for (typeof((c).begin()) i = (c).begin(); i != (c).end(); ++i)
#define exist(s, e) ((s).find(e) != (s).end())
#define range(i, a, b) for (int i = (a); i < (b); ++i)
#define rep(i, n) range(i, 0, n)
#define clr(a, b) memset((a), (b), sizeof(a))
#define dump(x) cerr << #x << " = " << (x) << endl;
#define debug(x)                                                               \\
  cerr << #x << " = " << (x) << " (L" << __LINE__ << ")"                       \\
       << " " << __FILE__ << endl;

typedef long double D;
const D eps = 1e-10;
const D pi = acos(-1.0);
const ll INF = 1LL << 62;
const int inf = 1 << 29;

double dp[10010][21][21];
int x[20], y[20];
D dist[20][20];

bool ok[20][20][20];

int main(void) {
  int n;
  cin >> n;
  D r, theta;
  cin >> r >> theta;
  int limit = 1 * r;

  rep(i, n) cin >> x[i] >> y[i];

  rep(i, n) rep(j, n) {
    int dx = (x[i] - x[j]);
    int dy = (y[i] - y[j]);
    dist[i][j] = sqrt(1.0 * dx * dx + 1.0 * dy * dy);
  }

  rep(i, limit + 1) rep(j, n + 1) rep(k, n + 1) dp[i][j][k] = inf;
  int ans = 0;
  range(cp, 1, n) {
    if (dist[cp][0] <= r) {
      dp[1][cp][0] = dist[cp][0], ans = 1;
    }
  }
  rep(pp, n) rep(cp, n) rep(np, n) {
    if (pp == cp)
      continue;
    if (cp == np)
      continue;
    int cx = x[cp] - x[pp], cy = y[cp] - y[pp];
    int nx = x[np] - x[cp], ny = y[np] - y[cp];
    D dot = 1.0 * cx * nx + 1.0 * cy * ny;
    dot /= (dist[cp][pp] * dist[np][cp]);
    dot = max<D>(-1, dot);
    dot = min<D>(1, dot);
    D angle = acos(dot);
    angle *= 180.0 / pi;
    if (angle > 180.0)
      angle = 360.0 - angle;
    if (angle <= theta)
      ok[pp][cp][np] = true;
  }

  rep(i, limit) rep(cp, n) rep(pp, n) {
    if (dp[i][cp][pp] == inf)
      continue;
    if (cp == pp)
      continue;
    rep(np, n) {
      if (np == cp)
        continue;
      D add = dist[cp][np];
      if (dp[i][cp][pp] + add > r)
        continue;
      if (ok[pp][cp][np] == false)
        continue;
      dp[i + 1][np][cp] = min<D>(dp[i + 1][np][cp], dp[i][cp][pp] + add);
      ans = max(ans, i + 1);
    }
  }

  cout << ans << endl;
  return 0;
}

Error: TLE

Fixed submission:

#include <bits/stdc++.h>

using namespace std;

inline int toInt(string s) {
  int v;
  istringstream sin(s);
  sin >> v;
  return v;
}
template <class T> inline string toString(T x) {
  ostringstream sout;
  sout << x;
  return sout.str();
}
template <class T> inline T sqr(T x) { return x * x; }

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<string> vs;
typedef pair<int, int> pii;
typedef long long ll;

#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define pb push_back
#define mp make_pair
#define each(i, c)                                                             \\
  for (typeof((c).begin()) i = (c).begin(); i != (c).end(); ++i)
#define exist(s, e) ((s).find(e) != (s).end())
#define range(i, a, b) for (int i = (a); i < (b); ++i)
#define rep(i, n) range(i, 0, n)
#define clr(a, b) memset((a), (b), sizeof(a))
#define dump(x) cerr << #x << " = " << (x) << endl;
#define debug(x)                                                               \\
  cerr << #x << " = " << (x) << " (L" << __LINE__ << ")"                       \\
       << " " << __FILE__ << endl;

typedef long double D;
const D eps = 1e-10;
const D pi = acos(-1.0);
const ll INF = 1LL << 62;
const int inf = 1 << 29;

double dp[10010][21][21];
int x[20], y[20];

inline D dist(int i, int j) {
  int dx = (x[i] - x[j]);
  int dy = (y[i] - y[j]);
  return sqrt(1.0 * dx * dx + 1.0 * dy * dy);
}

int main(void) {
  int n;
  cin >> n;
  D r, theta;
  cin >> r >> theta;
  int limit = 1 * r;

  rep(i, n) cin >> x[i] >> y[i];

  rep(i, limit + 1) rep(j, n + 1) rep(k, n + 1) dp[i][j][k] = inf;
  dp[0][0][n] = 0.0;

  rep(i, limit) rep(cp, n) rep(pp, n + 1) {
    if (dp[i][cp][pp] == inf)
      continue;
    if (i > 0 && pp == n)
      continue;
    if (cp == pp)
      continue;
    rep(np, n) {
      if (np == cp)
        continue;
      D add = dist(cp, np);
      int cx = x[cp] - x[pp], cy = y[cp] - y[pp];
      int nx = x[np] - x[cp], ny = y[np] - y[cp];
      D dot = 1.0 * cx * nx + 1.0 * cy * ny;
      dot /= (dist(cp, pp) * dist(np, cp));
      dot = max<D>(-1, dot);
      dot = min<D>(1, dot);
      D angle = acos(dot);
      angle *= 180.0 / pi;

      if (angle > 180.0)
        angle = 360.0 - angle;
      if (pp != n && angle > theta)
        continue;
      // cerr << np << " "  << cp << " " << pp << " " << angle << endl;
      if (dp[i][cp][pp] + add > r)
        continue;
      dp[i + 1][np][cp] = min<D>(dp[i + 1][np][cp], dp[i][cp][pp] + add);
    }
  }

  int ans = 0;
  rep(i, limit + 1) rep(cp, n) rep(pp, n) {
    if (dp[i][cp][pp] <= r)
      ans = max(ans, i);
  }
  cout << ans << endl;
  return 0;
}