Submission #1813790

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Source Code Expand

#include <iostream>
#include <sstream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <ctime>
#include <cstring>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <map>
#include <set>
#include <bitset>
#include <numeric>
#include <utility>
#include <iomanip>
#include <algorithm>
#include <functional>
using namespace std;
 
#define COUT(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl
#define EACH(i, s) for (__typeof__((s).begin()) i = (s).begin(); i != (s).end(); ++i)
 
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<class T1, class T2> ostream& operator << (ostream &s, pair<T1,T2> P)
{ return s << '<' << P.first << ", " << P.second << '>'; }
template<class T> ostream& operator << (ostream &s, vector<T> P)
{ for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s; }
template<class T> ostream& operator << (ostream &s, vector<vector<T> > P)
{ for (int i = 0; i < P.size(); ++i) { s << endl << P[i]; } return s << endl; }
template<class T1, class T2> ostream& operator << (ostream &s, map<T1,T2> P)
{ EACH(it, P) { s << "<" << it->first << "->" << it->second << "> "; } return s << endl; }




typedef int VAL;
const int MAX_B = 610000;

int SIZE_B;
struct BIT {
	VAL dat[MAX_B + 1];

	void init(int n = 1) {
		SIZE_B = n;
		for (int i = 0; i <= SIZE_B; ++i) dat[i] = 0;
	}

	inline void add(int a, VAL x) {
		for (int i = a; i <= SIZE_B; i += i & -i)
			dat[i] = dat[i] + x;
	}

	inline VAL sum(int a) {
		VAL res = 0;
		for (int i = a; i > 0; i -= i & -i)
			res = res + dat[i];
		return res;
	}

	inline VAL sum(int a, int b) {
		return sum(b - 1) - sum(a - 1);
	}

	void print() {
		for (int i = 1; i <= SIZE_B; ++i) cout << sum(i, i + 1) << ",";
		cout << endl;
	}
};

BIT bit;

int N;
const int MAX = 510000;
typedef pair<pair<double,double>, double> LINE;
vector<LINE> lines;

bool cmpx(LINE a, LINE b) {
  return -a.first.first / a.first.second > -b.first.first / b.first.second;
}

bool cmpy(LINE a, LINE b) {
  return -a.first.second / a.first.first > -b.first.second / b.first.first;
}

double inter[MAX];
map<double,int> ma;
int id[MAX];


double solve(bool isx) {
  if (isx) sort(lines.begin(), lines.end(), cmpx);
  else sort(lines.begin(), lines.end(), cmpy);

	//COUT(lines);

  double lo = -(1LL<<30), hi = 1LL<<30;
  for (int iter = 0; iter < 100; ++iter) {
		double mid = (lo + hi) / 2;
		ma.clear();

		for (int i = 0; i < N; ++i) {
		  LINE line = lines[i];
		  double po = 0;
			if (isx) po = (line.second - line.first.first*mid) / line.first.second;
		  else po = (line.second - line.first.second*mid) / line.first.first;
		  inter[i] = po;
			ma[po] = 0;	
		}
		int co = 0;
		for (map<double,int>::iterator it = ma.begin(); it != ma.end(); ++it) {
			it->second = co++;
		}
		for (int i = 0; i < N; ++i) {
		  id[i] = ma[inter[i]];
			//cout << i << ": " << lines[i] << ", " << "(" << mid << ")" << inter[i] << "; " << id[i] << endl;
		}

		int count = 0;
		bit.init(N+5);
		for (int i = 0; i < N; ++i) {
		  int add = id[i];
		  int tmp = bit.sum(add+2, N+3);
		  count += tmp;
		  bit.add(add+1, 1);
		}

		int aida = (N*(N-1)/2 - 1)/2;
		if (count >= aida + 1) hi = mid;
		else lo = mid;

		//cout << mid << ": " << ", " << aida << ": " << count << endl;
  }

  return hi;
}


int main() {
  while (cin >> N) {
		lines.resize(N);
		for (int i = 0; i < N; ++i) {
			cin >> lines[i].first.first >> lines[i].first.second >> lines[i].second;
		}
		double X = solve(true);
		double Y = solve(false);
		cout << fixed << setprecision(10) << X << " " << Y << endl;
  }
}

Submission Info

Judge Result