Cod sursa(job #2962091)

Utilizator David_PatranjelDavid Patranjel David_Patranjel Data 7 ianuarie 2023 18:58:20
Problema Cuplaj maxim in graf bipartit Scor 50
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 5.37 kb
///O(n*m*m)
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define INFINITY 999999999
int l, r, e;
using namespace std;
class Graf{
private:
    int noNodes;
    int noEdges;
    vector<vector<pair<int, int>>> graf_c;
    bool fromZero;
    bool oriented;
    bool hasCosts;
private:
    bool constructSTNesaturatedBF(int s, int t, vector<vector<int>>& f,
                                  vector<vector<int>>& graf_t, vector<int>& tata, vector<bool>& viz);
    void revizFlux(int s, int t, vector<vector<int>>& f, vector<int>& tata, int& ip);
public:
    Graf(int noNodes_, int noEdges_, const vector<vector<int>>& edges, bool fromZero_, bool oriented_, bool hasCosts_);
    int EndmondsKarp(vector<vector<int>>& f);
    int getNodes(){
        return noNodes;
    }
    ~Graf() = default;
};

void citireFisier(int& n, int &m, vector<vector<int>>& G);
void testEdmondsKarp(Graf& my_graf);

int main()
{
    int n, m;
    vector<vector<int>> G;
    citireFisier(n, m, G);
    Graf my_graf{n, m, G, true, true, true};
    testEdmondsKarp(my_graf);
    return 0;
}
void citireFisier(int& n, int &m, vector<vector<int>>& G){
    int x, y;
    ifstream fin("cuplaj.in");
    fin>>l>>r>>e;

    for(int i = 1; i <= e; ++i){
        fin>>x>>y;
        G.push_back({x, y + l, 1});
    }

    for(int i = 1; i <= l; ++i){
        G.push_back({0, i, 1});
    }

    for(int i = 1; i <= r; ++i){
        G.push_back({i + l, l + r + 1, 1});
    }

    m = l + r + e;
    n = l + r + 2;
    fin.close();
}

void testEdmondsKarp(Graf& my_graf){
    vector<vector<int>> f(my_graf.getNodes() + 1, vector<int>(my_graf.getNodes()+ 1, 0));
    ofstream fout("cuplaj.out");
    fout<<my_graf.EndmondsKarp(f)<<endl;
    for(int i = 1; i <= l; ++i){
        for(int j = 1; j <= r; ++j){
            if(f[i][j + l] == 1){
                fout<<i<<" "<<j<<endl;
            }
        }
    }
    fout.close();
}

Graf::Graf(int noNodes_, int noEdges_, const vector<vector<int>> &edges, bool fromZero_, bool oriented_, bool hasCosts_) {
    noNodes = noNodes_;
    noEdges = noEdges_;
    fromZero = fromZero_;
    oriented = oriented_;
    hasCosts = hasCosts_;
    if(hasCosts)
        graf_c.resize(noNodes+1);
    for(auto& edge:edges){
        int x = edge[0], y = edge[1];
        if(hasCosts) {
            int z = edge[2];
            graf_c[x].push_back(make_pair(y, z));
            if (!oriented)
                graf_c[y].push_back(make_pair(x, z));
        }
    }
}

bool Graf::constructSTNesaturatedBF(int s, int t, vector<vector<int>>& f,
                                         vector<vector<int>>& graf_t, vector<int>& tata, vector<bool>& viz){
    int i, v, c;
    fill(viz.begin(), viz.end(), false);
    queue<int> C;
    C.push(s);
    viz[s] = true;

    while(!C.empty()) {
        i = C.front();
        if(i == t){
            C.pop();
            continue;
        }
        for(auto& j:graf_c[i]) {
            v = j.first; c = j.second;
            if (!viz[v] && c > f[i][v]) { ///arc direct
                C.push(v);
                viz[v] = 1;
                tata[v] = i;
                if(v == t)
                    return true;
            }
        }
        for(auto& j:graf_t[i]){
            v = j;
            if(viz[v] == 0 && f[v][i] > 0){   ///arc invers
                C.push(v);
                viz[v] = 1;
                tata[v] = -i;
                if(v == t)
                    return true;
            }
        }
        C.pop();
    }
    if(viz[t])
        return true;
    return false;
}
void Graf::revizFlux(int s, int t, vector<vector<int>>& f, vector<int>& tata, int& ip){
    int nod = t, parent, mod_nod;
    do{
        mod_nod = abs(nod);
        parent = tata[mod_nod];
        if(parent >= 0){
            f[parent][mod_nod] += ip;
        }else{
            f[mod_nod][abs(parent)] -= ip;
        }
        nod = tata[mod_nod];
    }while(abs(nod) != s);
}
int Graf::EndmondsKarp(vector<vector<int>>& f){
    short offset = fromZero?1:0;
    int sum = 0, s = 1 - offset, t = noNodes - offset, minim;
    vector<vector<int>> graf_t(noNodes + 1);
    vector<bool> viz(noNodes + 1, false);
    vector<int> tata(noNodes + 1, 0);
    vector<vector<int>> c(noNodes + 1, vector<int>(noNodes + 1, 0));

    for(int i = 1 - offset; i <= noNodes - offset; ++i){
        for(auto& j:graf_c[i]){
            c[i][j.first] = j.second;
            graf_t[j.first].push_back(i);
        }
    }

    while(constructSTNesaturatedBF(s, t, f, graf_t, tata, viz)){
        for (auto& node: graf_t[t]) {
            if (f[node][t] == c[node][t] || !viz[node])
                continue;

            tata[t] = node;
            minim = INFINITY;

            int nod = t, parent, mod_nod;
            do{
                mod_nod = abs(nod);
                parent = tata[mod_nod];
                if(parent >= 0){
                    minim = min(minim, c[parent][mod_nod] - f[parent][mod_nod]);
                }else{
                    minim = min(minim, f[mod_nod][abs(parent)]);
                }
                nod = tata[mod_nod];
            }while(abs(nod) != s && minim != 0);
            if (minim == 0)
                continue;

            revizFlux(s, t, f, tata, minim);
            sum += minim;
        }
    }
    return sum;
}