勇者斗恶龙

题目：

Problem C: The Dragon of Loowater

Once upon a time, in the Kingdom of Loowater, a minor nuisance turned into a major problem.

The shores of Rellau Creek in central Loowater had always been a prime breeding ground for geese. Due to the lack of predators, the geese population was out of control. The people of Loowater mostly kept clear of the geese. Occasionally, a goose would attack one of the people, and perhaps bite off a finger or two, but in general, the people tolerated the geese as a minor nuisance.

One day, a freak mutation occurred, and one of the geese spawned a multi-headed fire-breathing dragon. When the dragon grew up, he threatened to burn the Kingdom of Loowater to a crisp. Loowater had a major problem. The king was alarmed, and called on his knights to slay the dragon and save the kingdom.

The knights explained: "To slay the dragon, we must chop off all its heads. Each knight can chop off one of the dragon's heads. The heads of the dragon are of different sizes. In order to chop off a head, a knight must be at least as tall as the diameter of the head. The knights' union demands that for chopping off a head, a knight must be paid a wage equal to one gold coin for each centimetre of the knight's height."

Would there be enough knights to defeat the dragon? The king called on his advisors to help him decide how many and which knights to hire. After having lost a lot of money building Mir Park, the king wanted to minimize the expense of slaying the dragon. As one of the advisors, your job was to help the king. You took it very seriously: if you failed, you and the whole kingdom would be burnt to a crisp!

Input Specification:

The input contains several test cases. The first line of each test case contains two integers between 1 and 20000 inclusive, indicating the number n of heads that the dragon has, and the number m of knights in the kingdom. The next n lines each contain an integer, and give the diameters of the dragon's heads, in centimetres. The following m lines each contain an integer, and specify the heights of the knights of Loowater, also in centimetres.

The last test case is followed by a line containing:

0 0

Output Specification:

For each test case, output a line containing the minimum number of gold coins that the king needs to pay to slay the dragon. If it is not possible for the knights of Loowater to slay the dragon, output the line:

Loowater is doomed!

Sample Input:

2 3547842 155100 0

Output for Sample Input:

11Loowater is doomed!

按照算法竞赛入门经典，可以先把两个数组排序，在从龙的头的大小，从小到大开始，一个个的对照勇士的能力大小，一个个的往后选。

选择的规则是：两个循环，从龙的头颅大小最小的开始，一个一个的对应，如果龙的头的大小要小于勇士的能力值，就选（此时选的，必定是最小的花费），依次往后做，直到龙的数目搞完。如果龙的头有剩余，或者其中一只龙不能在勇士的能力范围之内搞定，就输出搞不定。

代码如下：

#include<iostream>
#include<algorithm>
#define Ma 20001
using namespace std;
int main()
{
    int n, m;
    while(cin>>n>>m)
    {
        if(n == 0 && m == 0) break;
        int N[Ma], M[Ma];
    for(int i = 0; i < n; i++)
        cin>>N[i];
    for(int i = 0; i < m; i++)
        cin>>M[i];
    sort(N, N+n);//排序
    sort(M, M+m);
    int cost = 0;
    int cur = 0;
    for(int i = 0; i < n; i++)
    {                                             //龙头的循环
        for(int j = 0; j < m; j++)// 勇士能力值的循环
        {
            if(M[j] >= N[i])
            {
                cost+=M[j];
                cur++;
                M[j] = -1;
                break;
            }
        }
    }
    if(cur < n) cout<<"Loowater is doomed!"<<endl;
    else cout<<cost<<endl;
    }
    return 0;
}