Cod sursa(job #885327)

Utilizator mateicrnMatei Crn mateicrn Data 21 februarie 2013 20:35:34
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.86 kb
#include<iostream>
#include <fstream>
#include <queue>
using namespace std;

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

queue<int>q;
vector<int> a[100001];
int x0,n,d[100001];
void citire()
{
    int m,i,x,y;
    in>>n>>m>>x0;
    for(i=1;i<=m;i++)
    {
        in>>x>>y;
        a[x].push_back(y);
    }
}
void init()
{
    for(int i=1 ; i<=n ; i++)
        d[i] = -1;
}

void bfs(int x0)
{
    int x,y;
    init();
    q.push(x0);
    d[x0]=0;
    while(!q.empty())
    {
        x=q.front();
        q.pop();
        for(size_t i=0;i<a[x].size();i++)
        {
            y=a[x][i];
            if(d[y]==-1)
            {
                q.push(y);
                d[y]=1+d[x];
            }
        }
    }
}
int main()
{
    citire();
    bfs(x0);
    for(int i=1 ; i<=n ; i++) out << d[i] << " ";
    return 0;
}