USACO习题：Greedy Gift Givers

几个朋友给钱的问题。建立一个数组保存每个人的钱，收的加，出的减即可。

 

#include <iostream>
#include <fstream>
#include <string>
#include <map>
#include <vector>


using namespace std;


int main() {
    ofstream fout("gift1.out");
    ifstream fin("gift1.in");

    int np = 0;
    fin>>np; //get the number of people

    vector<string> people(np);
    //name mapping with money
    map<string,int> wallet;
    string name;
    for(int i =0 ; i<np;i++){
        fin>>name;
        wallet[name]=0;
        people[i]=name;
    }


    //calculate the money flow
    for(int i=0;i<np;i++){
        
        int money=0,number_of_friend=0,gift=0;
        fin>>name;
        fin>>money>>number_of_friend;
        string friend_name;

        //cout<<name<<" "<<money<<" "<<number_of_friend<<endl;
        if(number_of_friend==0)
            continue; //don't forget to check zero
        gift=(int)(money/number_of_friend);//guard cast

        //the giver gives his money out
        wallet[name] -= gift*number_of_friend;
        for(int j=0;j<number_of_friend;j++){
            fin>>friend_name;
            //the friend receives the giver's money
            wallet[friend_name]+=gift;
        }
    }

    //output the money
    for(vector<string>::iterator iter=people.begin();
            iter!=people.end();++iter)
        fout<<*iter<<" "<<wallet[*iter]<<endl;


    fin.close();
    fout.close();
    return 0;
}