题目来源：http://community.topcoder.com/stat?c=problem_statement&pm=12948

代码如下：

#include <algorithm>
#include <iostream>
#include <sstream>

#include <string>
#include <vector>
#include <stack>
#include <deque>
#include <queue>
#include <set>
#include <map>

#include <cstdio>
#include <cstdlib>
#include <cctype>
#include <cmath>
#include <cstring>
#include <ctime>
using namespace std;


/*************** Program Begin **********************/
bool cmp(pair<int, int> a, pair<int, int> b)
{
	return a.second > b.second;
}
class AlienAndHamburgers {
public:

    int getNumber(vector <int> type, vector <int> taste) {
	int A = 0;
	int n = type.size();
	vector < pair<int, int> > tt;

	for (int i = 0; i < n; i++) {
		tt.push_back( make_pair(type[i], taste[i]) );
	}
	sort(tt.begin(), tt.end(), cmp);

	set <int> kinds;
	bool v[60];
	for (int i = 0; i < 60; i++) {
		v[i] = false;
	}
	for (int i = 0; i < n; i++) {
		if (tt[i].second >= 0) {
			kinds.insert(tt[i].first);
			A += tt[i].second;
			v[i] = true;
		}
	}

	for (int i = 0; i < n; i++) {
		if (!v[i]) {
			set <int>::iterator it;
			it = kinds.find(tt[i].first);
			if (it != kinds.end()) {
				v[i] = true;
			}
		}
	}
	int Y = kinds.size();
	int ans = Y * A;
	for (int i = 0; i < n; i++) {
		if (!v[i]) {
			int m = tt[i].second;	
			kinds.insert(tt[i].first);
			++Y;
			if (Y == kinds.size()) {
				A += m;
				ans = max(ans, Y * A);
				v[i] = true;
			} else {
				--Y;
			}
		}
	}
	return ans;
    }
};
/************** Program End ************************/

SRM 605 D1 L1 ：AlienAndHamburgers，Greedy