// Tyler Rigsby, CSE 142
// Contains several examples using ArrayLists
// 
// Translation from array to ArrayList:
//      String[]             ArrayList<String>
//      new String[n]        new ArrayList<String>()
//      list[i]              list.get(i)
//      list[i] = val        list.set(i, val);
//      list.length          list.size()
// New operations:
//      list.add(val)        appends val to list
//      list.remove(i)       removes and returns the value at i
//      list.clear()         clears the entire ArrayList

import java.util.*;

public class ArrayListExamples {
    public static void main(String[] args) {
        ArrayList<String> list1 = new ArrayList<String>();
        list1.add("it's");
        list1.add("friday");
        list1.add("friday");
        list1.add("gotta");
        list1.add("get");
        list1.add("down");
        list1.add("on");
        list1.add("thursday");
        
        list1.set(7, "friday");
        
        System.out.println("list1 = " + list1);
        System.out.println("max length = " + maxLength(list1));
        removeEvenLength(list1);
        System.out.println("after removeEvenLength = " + list1);
        echo(list1);
        System.out.println("after echo = " + list1);
               
        ArrayList<Integer> list2 = new ArrayList<Integer>();
        list2.add(42);
        list2.add(17);
        list2.add(37);
        list2.add(54);
        
        System.out.println("list2 = " + list2);
        minToFront(list2);

        System.out.println("After minToFront = " + list2);
        
        // sorts an ArrayList
        Collections.sort(list1);

    }
    
    // returns the length of the longest String in the given list
    public static int maxLength(ArrayList<String> list) {
        int max = 0;
        for (int i = 0; i < list.size(); i++) {
            String s = list.get(i);
            if (s.length() > max) {
                max = s.length();
            }
        }
        return max;
    }

    // moves the minimum value to the front of the given list, otherwise
    // preserving the order of the elements
    public static void minToFront(ArrayList<Integer> list) {
        int minIndex = 0;
        for (int i = 1; i < list.size(); i++) {
            if (list.get(i) < list.get(minIndex)) {
                minIndex = i;
            }
        }
        int val = list.remove(minIndex);
        list.add(0, val);
        // or, list.add(0, list.remove(minIndex))
    }

    // removes from the list all strings of even length
    public static void removeEvenLength(ArrayList<String> list) {
        for (int i = 0; i < list.size(); i++) {
            String s = list.get(i);
            if (s.length() % 2 == 0) {
                list.remove(i);
                i--;
            }
        }
    }
    
    // replaces every value in the list with two of that value
    public static void echo(ArrayList<String> list) {
        for (int i = 0; i < list.size(); i += 2) {
            String s = list.get(i);
            list.add(i, s);
        }
    }
}