Problem p00775 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <algorithm>
#include <bitset>
#include <cctype>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>

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;

#define x first
#define y second

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

int main(void) {
  double res;
  for (int r, n; cin >> r >> n, r; cout << res << endl) {
    res = 0.;
    map<int, map<int, int>> shadows;
    rep(i, n) {
      int left, right, h;
      cin >> left >> right >> h;
      range(x, left, right) { shadows[x][x + 1] = max(shadows[x][x + 1], h); }
    }

    bool ok = false;
    for (; !ok; res += 0.0001) {
      pair<double, double> o = mp(0., -r + res);

      range(x, -r, r) {
        rep(i, 2) {
          double d = sqr(x + i - o.x) + sqr(shadows[x][x + 1] - o.y);

          if (d <= (double)sqr(r)) {
            ok = true;
            break;
          }
        }
      }
    }
  }

  return 0;
}

Error: TLE

Fixed submission:

#include <algorithm>
#include <bitset>
#include <cctype>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>

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;

#define x first
#define y second

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

int main(void) {
  double res;
  for (int r, n; cin >> r >> n, r; cout << res << endl) {
    res = 0.;
    map<int, map<int, int>> shadows;
    rep(i, n) {
      int left, right, h;
      cin >> left >> right >> h;
      range(x, left, right) { shadows[x][x + 1] = max(shadows[x][x + 1], h); }
    }

    bool ok = false;
    for (; !ok; res += 0.00001) {
      pair<double, double> o = mp(0., -r + res);

      range(x, -r, r) {
        rep(i, 2) {
          double d = sqr(x + i - o.x) + sqr(shadows[x][x + 1] - o.y);

          if (d < (double)sqr(r)) {
            ok = true;
            break;
          }
        }
      }
    }
    res -= 0.0001;
  }

  return 0;
}