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  1. import java.util.*;
  2.  
  3. class MapReduce {
  4.  
  5.     private Map<Integer, HashSet<String>> intermediate = new LinkedHashMap<>();
  6.     private Set<Integer> finalResult = new HashSet<>();
  7.  
  8.     Set<Integer> execute(int[] R, int[] S) {
  9.         for (int aR : R) {
  10.             mapper(aR, "R");
  11.         }
  12.         for (int aS : S) {
  13.             mapper(aS, "S");
  14.         }
  15.  
  16.         Iterator it = intermediate.entrySet().iterator();
  17.         while (it.hasNext()) {
  18.             Map.Entry<Integer, HashSet<String>> pair = (Map.Entry) it.next();
  19.             reducer(pair.getKey(), pair.getValue());
  20.             it.remove();
  21.         }
  22.         return finalResult;
  23.     }
  24.  
  25.     private void emit(int obj) {
  26.         finalResult.add(obj);
  27.     }
  28.  
  29.     private void reducer(int key, HashSet value) {
  30.         // Fill up the question mark in the reducer function!
  31.         if (value.size() == 2) {
  32.             emit(key);
  33.         }
  34.     }
  35.  
  36.     private void mapper(int key, String value) {
  37.         emitIntermediate(key, value);
  38.     }
  39.  
  40.     private void emitIntermediate(int key, String value) {
  41.         if (intermediate.containsKey(key)) {
  42.             intermediate.get(key).add(value);
  43.             return;
  44.         }
  45.         intermediate.put(key, new HashSet<String>() {{
  46.             add(value);
  47.         }});
  48.     }
  49. }
  50.  
  51. public class Main {
  52.  
  53.     public static void main(String[] arg) {
  54.  
  55.         Scanner sc = new Scanner(System.in);
  56.         int Nr = sc.nextInt();
  57.         int Ns = sc.nextInt();
  58.         int[] R = new int[Nr];
  59.         int[] S = new int[Ns];
  60.         for (int i = 0; i < Nr; i++) {
  61.             R[i] = sc.nextInt();
  62.         }
  63.  
  64.         for (int i = 0; i < Ns; i++) {
  65.             S[i] = sc.nextInt();
  66.         }
  67.  
  68.         MapReduce mapReduceJob = new MapReduce();
  69.         Set<Integer> result = mapReduceJob.execute(R, S);
  70.  
  71.         result.forEach(System.out::println);
  72.     }
  73.  
  74. }
Success #stdin #stdout 0.26s 321408KB
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https://ideone.com/eF2Xzf
language:
Java (HotSpot 12)
created:
8 years ago
visibility:
public

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