ZOJ2229 POJ1922 HDU1445 Ride to School

简单的贪心。对于出发时间小于0的车不予考虑，主要因为太快了追不上，太慢了追上了也没用

/*******************************************************************************
 # Author : Neo Fung
 # Email : [email protected]
 # Last modified: 2012-01-09 20:59
 # Filename: ZOJ2229 POJ1922 HDU1445 Ride to School.cpp
 # Description : 
 ******************************************************************************/
#ifdef _MSC_VER
#define DEBUG
#endif

#include <fstream>
#include <stdio.h>
#include <iostream>
#include <string.h>
#include <string>
//#include <memory.h>
#include <limits.h>
#include <algorithm>
#include <math.h>
#include <numeric>
#include <functional>
#include <ctype.h>
#define MAX 10010
using namespace std;


int main(void)
{
#ifdef DEBUG  
  freopen("../stdin.txt","r",stdin);
  freopen("../stdout.txt","w",stdout); 
#endif  

	int n;
	double speed,time;

	while(scanf("%d",&n)&&n)
	{
		double arrive_time=100000000.0;
		for(int i=0;i<n;++i)
		{
			scanf("%lf%lf",&speed,&time);
			if(time<0.0)
				continue;
			arrive_time=min(arrive_time,time+4.5/speed*3600);
		}
		printf("%d\n",static_cast<int>(ceil(arrive_time)));
	}

  return 0;
}