Algotithms

 
 
 

//¿Que interfaz es implementada por java.util.Hashtable? 
		public class Hashtable<K,V>
extends Dictionary<K,V>
implements Map<K,V>, Cloneable, Serializable


//	Que método se utiliza para iniciar la ejecución de un thread? 
			metodo start.

  
 Arrays.sort(myArray);
   System.out.println(myArray[myArray.length-1]);



for ( int i=0; i < n ;i++){
  for (int j=0;  j<n;j++){
    dibujo[x][i] = "_";
  }
  dibujo[i][n - i - 1] = "X";
  dibujo[i][i] = "X";  
}

for ( int i=0; i < n ;i++){
    for (int j=0;  j<n;j++){
      System.out.print(dibujo[x][i]);
    }
    System.out.println();
  }



int cola=n;
int punta=0;
for ( int i=0; i < n ;i++){
    for (int j=0;  j<n;j++){
      if(j==cola || j===punta) 
      {System.out.print('X');}
      else
      {System.out.print('_');}
    }
    cola--;
    punta++;
  }


  import java.util.*;

  public class MyClass {
      static int[] myArray = {1,2,2,4,5,6,7,8,8,8};
      public static void main(String args[]) {
      
         Map<Integer, Integer> occurrences = new HashMap<Integer, Integer>();
          for ( Integer word : myArray ) {
             Integer oldCount = occurrences.get(word);
             if ( oldCount == null ) {
                oldCount = 0;
             }
             occurrences.put(word, oldCount + 1);
          }
          //System.out.println(occurrences);
          Integer Maxkey=occurrences.entrySet().stream().max((entry1, entry2) -> entry1.getValue() > entry2.getValue() ? 1 : -1).get().getKey();
          System.out.println("Longest: "+occurrences.get(Maxkey));
          System.out.println("Number: "+Maxkey);
      }
  }


  import java.util.*;

  public class MyClass {
      static String[] myArray = {"a", "b", "c", "d", "d", "c", "b", "a"};
      public static void main(String args[]) {
          String[] mirror=Arrays.copyOfRange(myArray,0,myArray.length/2);
          String[] mirror2=Arrays.copyOfRange(myArray,myArray.length/2,myArray.length);
          Collections.reverse(Arrays.asList(mirror2));
          System.out.println(Arrays.toString(mirror));
          System.out.println(Arrays.toString(mirror2));
          System.out.println(Arrays.toString(mirror).equals(Arrays.toString(mirror2)));
          String res=Arrays.toString(mirror).equals(Arrays.toString(mirror2))?"Symmetric":"Asymmetric";
          System.out.println(res);
      }
  }
  
  //histograma 
  
  public static void main (String args[]) {
  
     int  size=Arrays.stream(myArray).max().getAsInt();
     Map<Integer, String> occurrences = new HashMap<Integer, String>();
          for ( Integer word : myArray ) 
          {  
             String oldCount = null;
             oldCount = occurrences.get(word);
             if ( oldCount == null ) {
                occurrences.put(word,  "*");
                continue;
             }
             occurrences.put(word, oldCount + "*");
          }
        
        //fill not present 
        for (int x=1;x<= size;x++ )
        {
            String pos = occurrences.get(x);
            if ( pos == null ) { System.out.println(x+": "); continue; }
            System.out.println(x+": "+pos);
        }
}