Cod sursa(job #2678080)

Utilizator SoranaAureliaCatrina Sorana SoranaAurelia Data 28 noiembrie 2020 09:51:48
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.92 kb
#include <fstream>
#include <queue>
#include <vector>
#define NMAX 100005
using namespace std;

ifstream f("bfs.in");
ofstream g("bfs.out");

int n, m, s;
vector<int> graph[NMAX];
queue<pair<int, int>> Q;
int d[NMAX];

void init(){
    for(int i=1; i<=n; i++){
        d[i] = -1;
    }
}


void citire(){
    int x, y;
    f>>n>>m>>s;
    init();
    for(int i=0; i<m; i++){
        f>>x>>y;
        graph[x].push_back(y);
    }
}


void bfs(){
    d[s] = 0;
    Q.push({s, 0});

    while(!Q.empty()){
        int vf = Q.front().first;
        int dist = Q.front().second + 1;
        for(auto &v:graph[vf])
            if(d[v] == -1){
                Q.push({v, dist});
                d[v] = dist;
            }
        Q.pop();
    }
}

void afisare(){
    for(int i=1; i<=n; i++)
        g<<d[i]<<" ";
}

int main()
{
    citire();
    bfs();
    afisare();
    return 0;
}