Cod sursa(job #2796698)

Utilizator Teodor_AxinteAxinte Teodor-Ionut Teodor_Axinte Data 8 noiembrie 2021 17:37:28
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 2.17 kb
#include <bits/stdc++.h>

using namespace std;

//ifstream fin("dfs.in");
ifstream fin("bfs.in");
ofstream fout("bfs.out");
//ofstream fout("dfs.out");

class Graf{
private:
    int n,m,nod_plecare;
    static const int N=100010;
    vector<int> v[N];
    int ans[N]={0};
    queue<pair<int,int>>q;
    bitset <N> viz;

public:
    Graf();
    ~Graf();
    void add_edge(int,int);
    void dfs(int);
    void bfs();
    void citire_Graf_neorientat();
    void citire_Graf_orientat_bfs();
    int nr_connected_components();
};

Graf::Graf() {

}

Graf::~Graf() {

}

void Graf::add_edge(int x, int y){
    v[x].push_back(y);
    v[y].push_back(x);
}

void Graf::dfs(int node){
    viz[node] = 1;
    for(auto it:v[node])
        if(!viz[it])
            dfs(it);
}

int Graf::nr_connected_components()  {
    int ct=0;
    for(int i=1;i<=this->n;i++)
        if(!viz[i]){
            dfs(i);
            ct++;
        }
    return ct;
}

void Graf::citire_Graf_neorientat(){
    int nr_noduri,nr_muchii;
    fin>>nr_noduri>>nr_muchii;
    this->n = nr_noduri;
    this->m = nr_muchii;

    for(int i=1;i<=m;i++){
        int x,y;
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
}

void Graf::citire_Graf_orientat_bfs() {
    int nr_noduri,nr_muchii,plecare;
    fin>>nr_noduri>>nr_muchii>>plecare;
    this->n = nr_noduri;
    this->m = nr_muchii;
    this->nod_plecare = plecare;

    q.push(make_pair(this->nod_plecare,0));
    for(int i=1;i<=this->m;i++)
    {
        int x,y;
        fin>>x>>y;
        v[x].push_back(y);
    }
}

void Graf::bfs() {
    while(!q.empty()){
        pair<int,int> dp = q.front();
        int x =dp.first;
        int y = dp.second;
        ans[x] =y;
        for(auto it:v[x])
            if(!viz[it]){
                viz[it]=1;
                q.push(make_pair(it,y+1));
            }
        q.pop();
    }

    ans[this->nod_plecare] = 0;
    for(int i=1;i<=n;i++){
        if(ans[i]==0 && i!= this->nod_plecare)
            ans[i]=-1;
        fout<<ans[i]<<" ";
    }
}

int main(){
    /*
    Graf G;
    G.citire_Graf_neorientat();
    fout<<G.nr_connected_components();
    */

    Graf G;
    G.citire_Graf_orientat_bfs();
    G.bfs();
    return 0;
}