Pagini recente » Cod sursa (job #539209) | Cod sursa (job #1443493) | Cod sursa (job #175290) | Cod sursa (job #2890378) | Cod sursa (job #3266268)
import java.io.*;
import java.util.*;
public class Main {
public static class DirectedGraph {
private List<Integer>[] adjList;
public DirectedGraph(int N) {
adjList = (List<Integer>[]) new List[N+1];
}
public int size() {
return adjList.length;
}
public Collection<Integer> neighbors(int u) {
return adjList[u];
}
public void addEdge(int u, int v) {
if (adjList[u] == null) {
adjList[u] = new LinkedList<>();
}
adjList[u].add(v);
}
}
public static class BFS {
private DirectedGraph g;
private int[] levels;
// private boolean[] visited;
public BFS(DirectedGraph g) {
this.g = Objects.requireNonNull(g);
levels = new int[g.size()];
// visited = new boolean[g.size()];
}
public void visit(int source) {
Queue<Integer> q = new LinkedList<>();
levels[source] = 0;
// visited[source] = true;
q.offer(source);
while(!q.isEmpty()) {
int u = q.poll();
Collection<Integer> neighbors = g.neighbors(u);
if (neighbors != null) {
for (int v : neighbors) {
if (levels[v] == 0 && v != source) {
levels[v] = levels[u] + 1;
q.offer(v);
}
}
}
}
}
}
public static void main(String[] args) throws IOException {
try (BufferedReader reader = new BufferedReader(new FileReader("bfs.in"));
PrintStream ps = new PrintStream(new FileOutputStream("bfs.out"), true)) {
StringTokenizer st = new StringTokenizer(reader.readLine());
int N = Integer.parseInt(st.nextToken());
int M = Integer.parseInt(st.nextToken());
int source = Integer.parseInt(st.nextToken());
DirectedGraph g = new DirectedGraph(N);
for (int i = 0; i < M; i++) {
st = new StringTokenizer(reader.readLine());
int u = Integer.parseInt(st.nextToken());
int v = Integer.parseInt(st.nextToken());
g.addEdge(u, v);
}
BFS bfs = new BFS(g);
bfs.visit(source);
for (int i = 1; i < g.size(); i++) {
if (bfs.levels[i] == 0 && source != i) {
ps.print(-1);
ps.print(" ");
} else {
ps.print(bfs.levels[i]);
ps.print(" ");
}
}
ps.println();
}
}
}