Cod sursa(job #2548321)

Utilizator Mirela_MagdalenaCatrina Mirela Mirela_Magdalena Data 16 februarie 2020 15:22:03
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.96 kb
#define NMAX 100005
#include <fstream>
#include <queue>
#include <vector>
using namespace std;

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

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

void init()
{
    for(int i = 0; i <= n; ++i)
        d[i] = -1;
}






void read()
{
    int x, y;

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

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

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

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

int main()
{
    read();
    bfs();
    write();
    return 0;
}