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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. {
  10. 	public static void main (String[] args) throws java.lang.Exception
  11. 	{
  12. 		String input[] = {"1 2", "2 4", "5 6", "4 7", "3 5", "8 9", "9 10", "11 12"};
  13.         System.out.println(answer(input));
  14. 	}
  15.  
  16.     public static List<Set<Integer>> answer(String[] pairs){
  17.  
  18.         List<Set<Integer>> list = new LinkedList<>();
  19.         // For each pair, separate the numbers
  20.         //Initialize with initial set
  21.         Set<Integer> init = new HashSet<>();
  22.         String[] splitted = pairs[0].split(" ");
  23.         init.add(Integer.parseInt(splitted[0]));
  24.         init.add(Integer.parseInt(splitted[1]));
  25.  
  26.         list.add(init);
  27.  
  28.         // To be used to maintain set record ahead
  29.         List<Set<Integer>> setsRecord = new LinkedList<>();
  30.  
  31.         boolean found = false;
  32.         Integer i1, i2;
  33.         for(String s : pairs){
  34.             i1 = Integer.parseInt((splitted = s.split(" "))[0]);
  35.             i2 = i2 = Integer.parseInt(splitted[1]);
  36.             for(Set<Integer> set : list){
  37.                 if(set.contains(i1) ||
  38.                         set.contains(i2)){
  39.                     // If element has already been found in a set, create a common set
  40.                     if(setsRecord.size() >= 1){
  41.                         setsRecord.get(0).addAll(set);
  42.                         // And remove this set
  43.                         list.remove(set);
  44.                     }
  45.                     else{
  46.                         set.add(i1);
  47.                         set.add(i2);
  48.                         // Maintain a record of this set
  49.                         setsRecord.add(set);
  50.                     }
  51.                     found = true;
  52.                 }
  53.             }
  54.             // Empty the set
  55.             setsRecord.clear();
  56.  
  57.             if(!found){
  58.                 Set<Integer> newSet = new HashSet<Integer>();
  59.                 newSet.add(i1);
  60.                 newSet.add(i2);
  61.                 list.add(newSet);
  62.             }
  63.             found = false;
  64.         }
  65.         return list;
  66.     }
  67. }
Success #stdin #stdout 0.04s 4386816KB
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stdin
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Standard input is empty
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[[1, 2, 4, 7], [3, 5, 6], [8, 9, 10], [11, 12]]
https://ideone.com/Bq8TbP
language:
Java (HotSpot 12)
created:
8 years ago
visibility:
public

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