Cod sursa(job #1001605)

Utilizator raulmuresanRaul Muresan raulmuresan Data 25 septembrie 2013 17:43:07
Problema BFS - Parcurgere in latime Scor 80
Compilator cpp Status done
Runda Arhiva educationala Marime 1.16 kb
#include <fstream>
#include <algorithm>
#include <queue>
#include <iostream>
#include <list>
#define NMAX 100005

using namespace std;

ifstream fin("bfs.in");
ofstream fout("bfs.out");
int n, m, cost[NMAX], start;

list <int> vecini[NMAX];
queue <int> q;

void citire() {
    int i, x, y;
    fin >> n >> m >> start;
    for (i = 1; i <= m; i++) {
        fin >> x >> y;
        vecini[x].push_back(y);
    }
    fin.close();
}

void bfs(int start) {
    int p, y;
    cost[start] = 0;
    q.push(start);
    while (!q.empty()) {
        p = q.front();
        q.pop();
        // vizitam toti vecinii punctului scos din coada
        while (not vecini[p].empty()) {
            y = vecini[p].front();
            vecini[p].pop_front();
            if (cost[y] == -1) {
                q.push(y); cost[y] = cost[p] + 1;
            }
        }
    }
}

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

void afiscost() {
    for (int i = 1; i <= n; i++)
        fout << cost[i] << ' ';
    fout.close();
}

int main() {
    citire();
    setcost();
    bfs(start);
    afiscost();
    return 0;
}