Cod sursa(job #670539)

Utilizator handz.FMI Andrei Tanasescu handz. Data 29 ianuarie 2012 13:52:12
Problema BFS - Parcurgere in latime Scor 50
Compilator cpp Status done
Runda Arhiva educationala Marime 1.36 kb
#include <iostream>
#include <fstream>
#define maxn 100005
#define maxm 1000005
using namespace std;
ifstream f("bfs.in");
ofstream g("bfs.out");

int n,m,coada[maxn],viz[maxn],i,j,s,cost[maxn];

typedef struct graf
{
    int nod;
    graf *next;
}*grf;

grf list[maxm];

void add_nod(int x,int y)
{
    grf q;
    q=new graf;
    q->nod=y;
    q->next=list[x];
    list[x]=q;
}

void citire_init()
{
    int x,y;
    f>>n; f>>m; f>>s;

    for(i=1; i<=m ;i++)
    {
        f>>x;
        f>>y;
        add_nod(x,y);
    }
    for(i=1; i<=n ;i++)
    {
        coada[i]=0;
        viz[i]=0;
        cost[i]=-1;
    }
    coada[1]=s;
    viz[s]=1;
    cost[s]=0;
}

int search_nod(int x,int y)
{
    grf q;
    q=list[x];
    while(q)
    {
        if(q->nod==y)
            return 1;
        q=q->next;
    }
    return 0;
}

void BFS()
{
    int z,k,pi,ps;
    pi=1;
    ps=1;
    while(ps<=pi)
    {
        z=coada[ps];
        for(k=1; k<=n ;k++)
        {
            if(search_nod(z,k) && !viz[k])
            {
                cost[k]=cost[z]+1;
                pi++;
                coada[pi]=k;
                viz[k]=1;
            }
        }
        ps++;
    }
}

int main()
{
    citire_init();
    BFS();
    for(int i=1; i<=n ;i++)
    {
        g<<cost[i]<<" ";
    }
    return 0;
}