List Identify Duplicates - Java Algorithm

Java examples for Algorithm:List

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Description

List Identify Duplicates

Demo Code


import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

public class ListIdentifyDuplicates {
  
  public static void main(String args []){
    List <Integer> ls = Arrays.asList(1,2,4,6,2,9,4,10,45,1);
  
    IdentifyDuplicates(ls);//from w w w .  ja va  2  s .  c o  m
    findDuplicatesMethod2(ls);
    findDuplicatesJava8(ls);
  }
  
  public static void IdentifyDuplicates(List <Integer> ls){
    
    System.out.println(ls);    
    Set <Integer> setFilteresDuplicates= new HashSet();
    Set <Integer> setWithoutDuplicates= new HashSet();
    
    for (Integer i : ls){
      if (! setWithoutDuplicates.add(i)){
        setFilteresDuplicates.add(i);
      }      
    }  
    System.out.println(setWithoutDuplicates);
    System.out.println("Method 1"+setFilteresDuplicates);
    
  }
  
  public static void findDuplicatesMethod2(List<Integer> input) {
      List<Integer> copy = new ArrayList<Integer>(input);
      for (Integer value : new HashSet<Integer>(input)) {
          copy.remove(value);
      }
      System.out.println(" Method 2:"+copy);
  }
  
   private static void findDuplicatesJava8(List<Integer> list) {
          Set<Integer> uniques = new HashSet<Integer>();
          System.out.println("Java 8 Streams"+list.stream().filter(e -> !uniques.add(e)).collect(Collectors.toSet()));
      }

}

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