Stable Matching (Gale Sharpley Algorithm), galesharpley

Stable Matching (Gale Sharpley Algorithm), galesharpley

Generate boys_rankings.txt and girls_rankings.txt

#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>#include <string>#include <sstream>#include <algorithm>#include <vector>#include <ctime>#include <fstream>using namespace std;vector<string> gen_boys(int number){    vector<string> result;    for(int i = 0; i < number; i++){        string boy = "B";        string s;        stringstream ss;        ss << i;        ss >> s;        boy.append(s);        result.push_back(boy);    }    return result;}vector<string> gen_girls(int number){    vector<string> result;    for(int i = 0; i < number; i++){        string boy = "G";        string s;        stringstream ss;        ss << i;        ss >> s;        boy.append(s);        result.push_back(boy);    }    return result;}vector<string> gen_ranking(vector<string> candidate){    random_shuffle(candidate.begin(), candidate.end());    return candidate;}void write_rankings(vector<string> people, vector<vector<string> > rankings, string out_file){    ofstream ofs(out_file.c_str());    if(ofs.fail()){        cerr << "Error: " << out_file << endl;        return;    }    for(int i = 0; i < people.size(); i++){        ofs << people[i] << ":";        for(int j = 0; j < rankings[i].size(); j++){            ofs << " " << rankings.at(i).at(j);        }        ofs << endl;    }    ofs.close();}int main(int argc, char ** argv){    srand(time(NULL));    int n = 200;    vector<string> boys = gen_boys(n);    vector<string> girls = gen_girls(n);    vector<vector<string> > boys_rankings;    vector<vector<string> > girls_rankings;    for(int i = 0; i < n; i++){        boys_rankings.push_back(gen_ranking(girls));        girls_rankings.push_back(gen_ranking(boys));    }    write_rankings(boys, boys_rankings, "boys_rankings.txt");    write_rankings(girls, girls_rankings, "girls_rankings.txt");    return 1;}

The following is the implementation of the Gale_Sharpley algorithm:

/*******************************************************   Projects : Implementation of Gale_Shapley algorithm*   Author   : johnsondu*   Time     : 2014-10-20 21:18*******************************************************/#include <iostream>#include <cstdio>#include <cmath>#include <algorithm>#include <fstream>#include <map>#include <vector>#include <cstring>#include <string>using namespace std;// The max size of the number of the boy.const int MAXN = 1000;// STL map, map boy's name to integer IDmap<string, int> boy;// STL map, map girl's name to integer IDmap<string, int> girl;// STL map, map corresponding boy's integer id to original string namemap<int, string> boyName;// STL map, map corresponding girl's integer id to original string namemap<int, string> girlName;// boy's preference ranking listint boysRankings[MAXN][MAXN];// girl's preference ranking listint girlsRankings[MAXN][MAXN];// the partner that boy matched. if no, marked as -1int boysPartner[MAXN];// the partner that girl matched. if no, marked as -1int girlsPartner[MAXN];/********************************************************  function description:*  let every boy and girl have it's own integer identity.*  key variable: <string, int>(map string name to integer*  id), <int, string>(map integer id to original string*  name)********************************************************/void SerialNumber(int &n){    ifstream in1("boys_rankings.txt");    ifstream in2("girls_rankings.txt");    string str;    int idb = 0;    // boy's id    int idg = 0;    // girl's id    while(getline(in1, str)){        string name = "";        int i = 0;        // get boys's name        while(str[i] != ':') name += str[i ++];        // map string to int.        boy[name] = idb ;        boyName[idb] = name;        idb ++;        // get the number of boys.        n ++;    }    while(getline(in2, str)){        string name = "";        int i = 0;        // get boys's name        while(str[i] != ':') name += str[i ++];        // map string to int.        girl[name] = idg;        girlName[idg] = name;        idg ++;    }    return;}/**********************************************   function description:*   Rereading two files, and get corresponding*   preference list of boys and girls. Save it*   in two dimension array: girlsRankings and*   boysRankings.*******************************************/void GetRankings(const int n){    ifstream in1("boys_rankings.txt");    ifstream in2("girls_rankings.txt");    string str;    // boy's id.    int id = 0;    while(getline(in1, str)){        string gname;        int i = 0;        int cnt = 0;        while(str[i] != ' ') i ++;        if(str[i] == ' ') i ++;        for(; i < str.size();)        {            gname = "";            while(str[i] != ' ' && i < str.size()) {                gname += str[i];                i ++;            }            boysRankings[id][cnt ++] = girl[gname];            if(str[i] == ' ') i ++;        }        id ++;    }    // girls id;    id = 0;    while(getline(in2, str)){        string bname;        // string size index.        int i = 0;        // the rankings in the girl's list.        int cnt = 0;        // prefix guarantee        while(str[i] != ' ') i ++;        if(str[i] == ' ') i ++;        for(; i < str.size();)        {            bname = "";            while(str[i] != ' ' && i < str.size()) {                bname += str[i];                i ++;            }            girlsRankings[id][cnt ++] = boy[bname];            if(str[i] == ' ') i ++;        }        id ++;    }    return ;}/**************************************   function description:*   set status for boys and girls,*   marked -1, no partner.**************************************/void InitStatus(const int n){    for(int i = 0; i < n; i ++)    {        boysPartner[i] = -1;        girlsPartner[i] = -1;    }}/*****************************************   function description:*   when one boy propose to one girl, and*   that girl already have a partner, this*   function is used for get ratings of*   two boys in that girl's preference list.*****************************************/int GetId(int boyId, int gId, const int n){    for(int i = 0; i < n; i ++)    {        if(girlsRankings[gId][i] == boyId) return i;    }    return -1;}/*****************************************   function description:*   once a man have dumped by a girl, set*   his status to no partner, and set his*   preference list of that girl as -1,*   stand for have been proposed before.*****************************************/void SetStatus(int boyId, int girlId, const int n){    boysPartner[boyId] = -1;    for(int i = 0; i < n; i ++)        if(boysRankings[boyId][i] == girlId){            boysRankings[boyId][i] = -1;            return;        }}/*****************************************   function description:*   Implementation of Gale_Shapley algorithm*****************************************/void StableMatch(const int n){    InitStatus(n);    while(true)    {        bool flag = false;        bool endOfFor = false;        // guarantee all the boys have a partner.        for(int i = 0; i < n; i ++){            if(boysPartner[i] == -1 || girlsPartner[i] == -1)            {                flag = true;                break;            }        }        if(!flag) break;        // for boy who have no partner.        for(int i = 0; i < n; i ++)        {            if(boysPartner[i] == -1){                for(int j = 0; j < n; j ++){                    // Since in the list of preference, j had rejected before.                    if(boysRankings[i][j] == -1) continue;                    // if j have no partner, then accept.                    if(girlsPartner[boysRankings[i][j]] == -1){                        boysPartner[i] = boysRankings[i][j];                        girlsPartner[boysRankings[i][j]] = i;                        endOfFor = true;                        break;                    }                    else{  // judge whether match is stable or not                        int useId = GetId(girlsPartner[boysRankings[i][j]], boysRankings[i][j], n);                        int curId = GetId(i, boysRankings[i][j], n);                        // if not stable                        if(curId < useId){                            // girl's partner's list, set -1 to mean the girl have rejected.                            SetStatus(girlsPartner[boysRankings[i][j]], boysRankings[i][j], n);                            boysPartner[i] = boysRankings[i][j];                            girlsPartner[boysRankings[i][j]] = i;                            endOfFor = true;                            break;                        }                    }                }            }            // find a partner, break out of the loop.            if(endOfFor) break;        }    }}/*****************************************   function description:*   print out result.*****************************************/void Print(const int n){    freopen("result.txt", "w", stdout);    cout << "The Matching Results are follows:" << endl;    for(int i = 0; i < n; i ++){        cout << boyName[i]            << "--" << girlName[boysPartner[i]] << "  " << endl;    }}/*****************************************   function description:*   Main function*****************************************/int main(){    int n = 0;    // let every boy and girl have it's own identity.    // and get integer ranking array list.    SerialNumber(n);    // get rankings.S    GetRankings(n);    // Stable match    StableMatch(n);    // Print solution    Print(n);    return 0;}