import java.util.*;
/*
ArrayList<E>

      Array                ArrayList
      -------------------------------------------
      String[] a           ArrayList<String> list
      a.length             list.size()
      a[i]                 list.get(i)
      a[i] = value         list.set(i, value)
      
      Additional ArrayList Methods
      -------------------------------------------
      list.add(value)      // Append the given value at the end of the list
      list.add(i, value)   // Add value at given index and shift ->
      list.remove(i)       // Remove value at given index, shift <-

*/
public class ArrayListLecture {
   public static void main(String[] args) {
      // Husky dubs = new Husky();  
      // ^ Declaration and initialization is same as other objects
      ArrayList<String> list = new ArrayList<String>();
      
            
      // Yo listen up here's a story about a little guy
      // that lives in a blue world
      list.add("Yo");      // 0
      list.add("listen");  // 1
      list.add("up");      // 2
      list.add("here's");  // 3
      list.add("a");       // 4
      list.add("about");   // 5
      list.add("a");       // 6
      list.add("little");  // 7
      list.add("guy");     // 8
      list.add("that");    // 9
      list.add("lives");   // 10
      list.add("in");      // 11
      list.add("a");       // 12
      list.add("cyan");    // 13
      list.add("world");   // 14
      
      System.out.println("Size: " + list.size()); 
      System.out.println(list);
      
      list.add(5, "story");
      // list.set(13, "blue"); Doesn't work b/c we added before 
      list.set(14, "blue");
      
      System.out.println(list);
      
      System.out.println();
      ArrayList<Integer> list2 = new ArrayList<Integer>();
      list2.add(5);
      list2.add(1);
      list2.add(3);
      list2.add(2);
      repeat(list2);
      System.out.println(list2);

      System.out.println();
      removeEvenLength(list);
      System.out.println(list);
   }
   
   
   
   // Wrapper classes
   // ArrayList's type must be a class (not primitive type)
   //    Integer
   //    Double
   //    Boolean
   //    Character
   
   // Replaces every value in the given list with two of that value
   // [5, 1, 2] - > [5, 5, 1, 1, 2, 2]
   public static void repeat(ArrayList<Integer> list) {
      for (int i = 0; i < list.size(); i += 2) {
         int value = list.get(i);
         list.add(i + 1, value);
      }
   
   }
   
   // Remove all Strings that have an even length from the given ArrayList
   // [hi, hii] -> [hii]
   public static void removeEvenLength(ArrayList<String> list) {
      // Solve by iterating backwards
      for (int i = list.size() - 1; i >= 0; i--) {
         String value = list.get(i);
         if (value.length() % 2 == 0) { // even length
            list.remove(i);
         }
      }
      
      /*
      // Solve by iterating forwards
      for (int i = 0; i < list.size(); i++) {
         // Do something with list.get(i)
         String value = list.get(i);
         if (value.length() % 2 == 0) { // even length
            list.remove(i);
            i--;
         }
      }
      */
   }
}