Cod sursa(job #796178)

Utilizator Viva12Ferentz Sergiu Viva12 Data 10 octombrie 2012 19:53:12
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.18 kb
#include <cstdio>
#include <vector>
#include <queue>
#define N 100005
using namespace std;

queue <int> Q;
vector <int> graph[N];

int start;
int n,m;
int viz[N];
int paths[N];
void citire()
{
    scanf("%d %d %d",&n,&m,&start);
    for(int i = 0 ; i < m; i++)
    {
        int x,y;
        scanf("%d %d",&x,&y);
        graph[x].push_back(y);
    }
}

void bfs(int start)
{
    for(int i = 0 ; i < N;i++)
    paths[i] = -1;

    paths[start] =0;
    viz[start] = 1;
    Q.push(start);
    while(!Q.empty())
        {

            int front= Q.front();
            for(int j = 0 ; j < graph[front].size();j++)
            {
                if(!viz[graph[front][j]])
                {
                    viz[graph[front][j]] = 1;
                    paths[graph[front][j]] = paths[front]+1;
                    Q.push(graph[front][j]);
                }
            }
            Q.pop();

        }
}

void afis()
{
    for(int i = 1; i<=n;i++)
    {
        printf("%d ",paths[i]);
    }
}


int main()
{
    freopen("bfs.in","r",stdin);
    freopen("bfs.out","w",stdout);
    citire();

    bfs(start);
    afis();
    return 0;
}