hdu-1070-Milk

Description

Ignatius drinks milk everyday, now he is in the supermarket and he wants to choose a bottle of milk. There are many kinds of milk in the supermarket, so Ignatius wants to know which kind of milk is the cheapest.

Here are some rules:
1. Ignatius will never drink the milk which is produced 6 days ago or earlier. That means if the milk is produced 2005-1-1, Ignatius will never drink this bottle after 2005-1-6(inclusive).
2. Ignatius drinks 200mL milk everyday.
3. If the milk left in the bottle is less than 200mL, Ignatius will throw it away.
4. All the milk in the supermarket is just produced today.

Note that Ignatius only wants to buy one bottle of milk, so if the volumn of a bottle is smaller than 200mL, you should ignore it.
Given some information of milk, your task is to tell Ignatius which milk is the cheapest.

 

Input

The input contains several test cases. The first line of the input is a single integer T which is the number of test cases. T test cases follow.
Each test case starts with a single integer N(1<=N<=100) which is the number of kinds of milk. Then N lines follow, each line contains a string S(the length will at most 100 characters) which indicate the brand of milk, then two integers for the brand: P(Yuan) which is the price of a bottle, V(mL) which is the volume of a bottle.

 

Output

For each test case, you should output the brand of the milk which is the cheapest. If there are more than one cheapest brand, you should output the one which has the largest volume.

 

Sample Input

      
      
      
      

       
       
       
       2
2
Yili 10 500
Mengniu 20 1000
4
Yili 10 500
Mengniu 20 1000
Guangming 1 199
Yanpai 40 10000 
      
      
      
      

 

Sample Output

      
      
      
      

       
       
       
       Mengniu
Mengniu 
      
      
      
      

Hint

In the first case, milk Yili can be drunk for 2 days, it costs 10 Yuan. Milk Mengniu can be drunk for 5 days, it costs 20 Yuan. So Mengniu is the cheapest.In the second case, milk Guangming should be ignored. Milk Yanpai can be drunk for 5 days, but it costs 40 Yuan. So Mengniu is the cheapest. 
         

 

简单的贪心题目，因为只喝5天以内的牛奶（包括5天）。那么一瓶牛奶只要能喝五天那么的不管它有多少升也只喝五天，所以当牛奶毫升量大于5天喝的量时就看谁价格更低了。保存价格更低的那个。此时如果价格是一样，那么就保存毫升量大的那个。输入一种处理一种与之前的做判断，保留最好的那个。即贪心。

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;

struct milk
{
    char s[1000];
    int p,v;
};

milk a[100005];

int main()
{
    int t,num,n;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d",&n);
        double m = 0;
        for(int i = 1; i<=n; i++)
        {
            scanf("%s%d%d",a[i].s,&a[i].p,&a[i].v);
            int cnt = 0;
            if(a[i].v < 200)
                continue;
            for(;;)
            {
                a[i].v-=200;
                cnt++;
                if(cnt == 5)
                    break;
                if(a[i].v <200)
                    break;
            }
            double val = (double)cnt/a[i].p;
                if(val > m )
                {
                    m = val;
                    num = i;
                }
                if(val == m)
                {
                    if(a[i].p < a[num].p)
                        num = i;
                    else if(a[i].p == a[num].p)
                    {
                        if(a[i].v > a[num].v)
                            num = i;
                    }
                }
        }
        printf("%s\n",a[num].s);
    }

    return 0;
}

这题是性价比问题，牛奶的平均价格=价格/天数，比较一下，当这个相等是，就要比较一下它们各自的容量了。考虑到这两点就可以了。