Cod sursa(job #728877)

Utilizator sana1987Laurentiu Dascalu sana1987 Data 29 martie 2012 05:21:35
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.16 kb
#include <vector>
#include <queue>
#include <cstdio>
#define N 100001

using namespace std;
vector<int> graph[N];
bool visited[N];
int dist[N];
int n;

void bfs(int start) {
    queue<int> q;

    q.push(start);
    visited[start] = true;
    dist[start] = 0;

    while (q.size() > 0) {
        int current = q.front();
        //printf("Scot din coada %d\n", current);
        q.pop();
        for (vector<int>::iterator it = graph[current].begin();
            it != graph[current].end();
            it++) {
            if (!visited[*it]) {
                q.push(*it);
                visited[*it] = true;
                dist[*it] = dist[current] + 1;
            }
        }
    }
}

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

    int m, start;
    scanf("%d %d %d ", &n, &m, &start);

    for (int i = 0; i < n; i++) {
        visited[i] = false;
        dist[i] = -1;
    }

    for (int i = 0; i < m; i++) {
        int x, y;
        scanf("%d %d ", &x, &y);
        graph[x - 1].push_back(y - 1);
    }

    bfs(start - 1);

    for (int i = 0; i < n; i++) {
        printf("%d ", dist[i]);
    }
    printf("\n");

    return 0;
}