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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.*;
  4. import java.lang.*;
  5. import java.io.*;
  6.  
  7. /* Name of the class has to be "Main" only if the class is public. */
  8. class Ideone{
  9. 	public static int[] bfs(List<List<Integer>> adj,int src,int n){
  10.     Queue<Integer> q = new LinkedList<>();
  11.     q.add(src);
  12.  
  13.     int lvl[] = new int[n+1];
  14.     Arrays.fill(lvl,-1);
  15.     lvl[src] = 0;
  16.  
  17.     int ways[] = new int[n+1];
  18.     ways[src] = 1;
  19.  
  20.     while(!q.isEmpty()){
  21.         int u = q.poll();
  22.  
  23.         for(int v : adj.get(u)){
  24.  
  25.             if(lvl[v] == -1){
  26.                 lvl[v] = lvl[u] + 1;
  27.                 ways[v] = ways[u];
  28.                 q.offer(v);
  29.             }
  30.             else if(lvl[v] == lvl[u] + 1){
  31.                 ways[v] += ways[u];
  32.             }
  33.         }
  34.     }
  35.     return ways;
  36. }
  37. 	public static void main (String[] args) throws java.lang.Exception{
  38. 		Scanner sc = new Scanner(System.in);
  39. 		int n = sc.nextInt();
  40. 		int m = sc.nextInt();
  41. 		List<List<Integer>> adj = new ArrayList<>();
  42. 		for(int i=0;i<=n;i++){
  43. 			adj.add(new ArrayList<>());
  44. 		}
  45.  
  46. 		for(int i=0;i<m;i++){
  47. 			int u = sc.nextInt();
  48. 			int v = sc.nextInt();
  49. 			adj.get(u).add(v);
  50. 			adj.get(v).add(u);
  51. 		}
  52. 		int src = sc.nextInt();
  53. 		int ways[] = bfs(adj,src,n);
  54.  
  55. 		for(int i=1;i<=n;i++){
  56. 			System.out.println(i+" "+ways[i]);
  57. 		}
  58. 	}
  59. }
Success #stdin #stdout 0.23s 60908KB
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https://ideone.com/1YxUBu
language:
Java (HotSpot 12)
created:
6 days ago
visibility:
public

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