【PAT-A】1139. First Contact (30)

http://blog.csdn.net/gl486546/article/details/78816363
看了别人家的代码觉得自己……emmmmmm
感觉中间用那个稀疏矩阵可以省很多事……

测试点0应该是正常的测试数据
测试点1&2 要考虑0000和-0000的情况（这两个点有0的输入） 以及输出是不是4位
测试点3&4 主要是同性的好友，要考虑到中间那两人（0-1-2-3）会不会重复（0=2 1=2 1=3）

code

// @author Birdy 2018.2.26
/*
Test point 1&2  0000 -0000
Test point 3&4 same gender test case
*/
#include<iostream>
#include<vector>
#include<map>
#include<cassert>
#include<string>
#include<algorithm>

using namespace std;

class relation
{
    string index;
    vector<string> samegender;
    vector<string> difgender;
public:
    relation(string index_t):index(index_t) {};
    void addfriend(string newfriend);
    bool checkrelation(string relation);
    vector<string> samegenderfriend() { return samegender; };
    string getindex() { return index; }
    //vector<int> difgenderfriend() { return difgender; };

};

class friendpair //record the output
{
public:
    int friend1;
    int friend2;
    friendpair(int f1, int f2) :friend1(f1), friend2(f2) {}
    void printpair();
};


class person
{
    map<string, class relation> index; // map person id to index
public:
    person() {};
    void addrelation(const string person1, const string person2);
    void addperson(const string id);
    map<string, class relation>::iterator findperson(const string id);
    vector<friendpair> findrelation(const string person1, const string person2);
};


void relation::addfriend(string newfriend)
{
    if ((index[0] == '-') == (newfriend[0] == '-'))
    {
        samegender.push_back(newfriend);
    }
    else
    {
        difgender.push_back(newfriend);
    }
}

bool relation::checkrelation(string relation)
{
    vector<string>::iterator findrelation;
    if ((index[0] == '-') == (relation[0] == '-'))
    {
        findrelation = std::find(samegender.begin(), samegender.end(), relation);
        if (findrelation == samegender.end())
            return false;
        else
            return true;
    }
    else
    {
        findrelation = std::find(difgender.begin(), difgender.end(), relation);
        if (findrelation == difgender.end())
            return false;
        else
            return true;
    }
    return false;
}


void person::addperson(const string id)
{
    index.insert(pair<string, class relation>(id, relation(id)));
}

map<string, class relation>::iterator person::findperson(const string id)
{
    map<string, class relation>::iterator it = index.find(id);
    if (it != index.end())
    {
        return it;
    }
    addperson(id);
    it = index.find(id);
    assert(it != index.end());
    return it;
}

vector<friendpair> person::findrelation(const string person1, const string person2)
{
    vector<friendpair> relation;
    vector<string> friend1 = (findperson(person1)->second).samegenderfriend();
    vector<string> friend2 = (findperson(person2)->second).samegenderfriend();

    for (vector<string>::iterator it1 = friend1.begin(); it1 < friend1.end(); it1++)
    {
        class relation friend_of_1 = findperson(*it1)->second;
        for (vector<string>::iterator it2 = friend2.begin(); it2 < friend2.end(); it2++)
        {
            if (friend_of_1.checkrelation(*it2))
            {
                if (person1 == *it2 || person2 == friend_of_1.getindex() || *it2 == friend_of_1.getindex()) continue;
                relation.push_back(friendpair(abs(atoi(friend_of_1.getindex().c_str())), abs(atoi((*it2).c_str()))) );//abs - output don't have -
                //cout << friend_of_1.getindex() << *it2 << endl;
            }
        }

    }
    //sort
    std::sort(relation.begin(), relation.end());
    return relation;
}

void person::addrelation(const string person1, const string person2)
{
    map<string, class relation>::iterator it1 = findperson(person1);
    map<string, class relation>::iterator it2 = findperson(person2);
    it1->second.addfriend(person2);
    it2->second.addfriend(person1);
}



bool operator<(const friendpair &s1, const friendpair &s2)
{
    return s1.friend1 == s2.friend1 ? s1.friend2 < s2.friend2 : s1.friend1 < s2.friend1;
}

void friendpair::printpair()
{
    //cout << friend1 << ' ' << friend2 << endl;
    printf("%04d %04d\n", friend1, friend2);
}

int main()
{
    int N, M, K;
    // what's the use of N?
    cin >> N >> M;

    person Person;
    int friend1, friend2;
    string IDstring1, IDstring2;
    // Test point 1 2 input contains 0
    for (int i = 0; i < M; i++)
    {
        cin >> IDstring1 >> IDstring2;
        Person.addrelation(IDstring1, IDstring2);
    }
    cin >> K;
    for (int i = 0; i < K; i++)
    {
        cin >> IDstring1 >> IDstring2;

        vector<friendpair> result = Person.findrelation(IDstring1, IDstring2);
        cout << result.size() << endl;
        for (vector<friendpair>::iterator it = result.begin(); it < result.end(); it++)
        {
            it->printpair();
        }

    }
    system("pause");
    return 0;
}