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| 1 | +import java.io.*; |
| 2 | +import java.util.*; |
| 3 | + |
| 4 | +/* |
| 5 | + * 상근이의 여행 |
| 6 | + */ |
| 7 | + |
| 8 | +public class DH_9372 { |
| 9 | + public static void main(String[] args) throws Exception { |
| 10 | + BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); |
| 11 | + StringTokenizer st; |
| 12 | + |
| 13 | + int T = Integer.parseInt(br.readLine()); |
| 14 | + |
| 15 | + Queue<Integer> q = new ArrayDeque<>(); |
| 16 | + StringBuilder sb = new StringBuilder(); |
| 17 | + |
| 18 | + for(int t = 0; t < T; t++) { |
| 19 | + st = new StringTokenizer(br.readLine()); |
| 20 | + |
| 21 | + int n = Integer.parseInt(st.nextToken()); |
| 22 | + int m = Integer.parseInt(st.nextToken()); |
| 23 | + |
| 24 | + boolean[] v = new boolean[n + 1]; |
| 25 | + ArrayList<Integer> adj[] = new ArrayList[n + 1]; |
| 26 | + for(int i = 0; i < adj.length; i++) adj[i] = new ArrayList<Integer>(); |
| 27 | + |
| 28 | + for(int i = 0; i < m; i++) { |
| 29 | + st = new StringTokenizer(br.readLine()); |
| 30 | + int a = Integer.parseInt(st.nextToken()); |
| 31 | + int b = Integer.parseInt(st.nextToken()); |
| 32 | + |
| 33 | + adj[a].add(b); |
| 34 | + adj[b].add(a); |
| 35 | + } |
| 36 | + |
| 37 | + int answer = 0; |
| 38 | + |
| 39 | + for(int i = 1; i < n; i++) { |
| 40 | + if(v[i]) continue; |
| 41 | + q.add(i); |
| 42 | + v[i] = true; |
| 43 | + |
| 44 | + while(!q.isEmpty()) { |
| 45 | + int current = q.poll(); |
| 46 | + |
| 47 | + for(int next: adj[current]) { |
| 48 | + if(v[next]) continue; |
| 49 | + answer += 1; |
| 50 | + q.add(next); |
| 51 | + v[next] = true; |
| 52 | + } |
| 53 | + } |
| 54 | + } |
| 55 | + |
| 56 | + sb.append(answer).append("\n"); |
| 57 | + } |
| 58 | + |
| 59 | + System.out.println(sb); |
| 60 | + } |
| 61 | +} |
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