vim challenge

gistfile1.java

import java.util.*;

/*
 * NORMAL MODE
 * challenge 0: motions
 *  hjkl - move in all directions
 *  www - move to next word 
 *  bbb - move to prev word, 
 *  eee - move to next word, 
 *  $ - move to end of line
 *  _ - move to beginning of line
 *  gg - move to top of file,
 *  G - move to end of file
 *  f<char> - move to next <char> in line
 *  t<char> - move to char before <char>
 *  F<char> - move to prev <char> in line
 *  T<char> - move to char ahead of <char> previously <- confusing
 *  x - delete character under cursor
 *  r<char> - replace character under cursor with <char> stay in normal mode
 *  :<line_num> - jump to line num
 *  } - jump to next paragraph
 *  { - jump to previous paragraph
 *
 * challenge 1: make it right - motion with www, delete with x, replace with r
 * The ccow iumpedd ovverr thhe mooon.
 *
 * INSERT MODE
 * <esc> - move out of insert mode
 * i - move into insert mode left of cursor
 * a - move into insert mode right of cursor
 * A - move into insert mode at end of line
 *
 * challenge 2: Insert
 * ---> There is text misng this .
 *  ---> There is some text missing from this line.
 *
 * challenge 3: Append
 * ---> There is some text missing from th
 *       There is some text missing from this line.
 * ---> There is also some text miss
 *      There is also some text missing here.
 *
 * DELETE
 * challenge 4: Delete - wwww, dw
 * ---> There are a some words fun that don't belong paper in this sentence.
 * 
 * challenge 5: Delete rest of this line - d$
 * ---> There are some fun words. I like turtles.
 *
 * What is this magic: OPERATORS AND MOTIONS!
 * Okay we have some primitives `d`, and a bunch of movements
 * We can combine delete `d` with any motion.
 * d$ - delete from current cursor position until end of line
 * dw - delete up until next word
 * db - delete backward until beginning of prev word
 *
 * MULTIPLIERS
 * What if we want to move 5 words forward?
 * 5w <- move 5
 * 5j <- 5 lines down
 *
 * What if you want to delete 5 words? prefix your command with a number
 * 5dw <- delete the next 5 words
 * ---> This is just a line with words you can move around in.
 *
 * MORE IN NORMAL MODE: OPERATING ON LINES
 * So often we need to operate on lines, vim is excellent at this
 * in insert mode. Double up on any command to apply it to a line
 *
 * dd <- delete the whole line
 *
 * -----> DELETE ME
 *
 * of course multipliers work
 * 2dd <- delete 2 lines
 *
 * -----> DELETE ME
 * -----> ME TOO
 *
 * `p` | `P` - vim does cool stuff when you delete. It puts it in your paste buffer.
 * p - pastes last deleted or yanked thing below cursor
 * P - pastes last deleted or yanked thing above cursor
 *
 * Put these in order using `p`
 * -----> 1st
 * -----> 3nd
 * -----> 2nd
 *
 * Put these in order using `P`
 * -----> 1st
 * -----> 3nd
 * -----> 2nd
 *
 * COPYING AKA YANK
 * yy - copys line
 * p - pastes below
 * P - pastes above
 *
 * Challenge: yank and paste this 10 times.
 * -----> I will not use the arrow keys
 * 
 * Challenge: yank and paste this 100 times.
 * you can use multipliers
 * -----> I will not use the arrow keys
 *
 * Favourites: 
 * ciw - delete word and move into insert mode
 * diw - delete whol word, stay in normal mode
 * ci( - delete up until surrounding parens
 * ci{ - delete up until braces
 *
 * SEARCHING
 * /<term>
 * n -> move to next
 * N -> move to prev (like less)
 */

public class Bst {

  public Bst left;
  public Bst right;
  public int value;

  /* try and search up until `,` */
  /* try ciw inside of the params */
  public Bst(int value, Bst left, Bst right) {
    this.value = value;
    this.left = left;
    this.right = right;
  }

  /*
   * Given a list of numbers create a balanced bst
   * First sort the list, then choose the median
   * and set its left and right child as the
   * median of the left and right half recursively.
   *
   * Running time: O(nlgn) from comparison-sort
   */
  //TODO: f( lciw int <esc>
  public static Bst createBalancedBst(String[] arr) { //<- fix this int[] ci( challenge
    Arrays.sort(arr);
    return createBalancedBstHelper(arr, 0, arr.length - 1);
  }

  private static Bst createBalancedBstHelper(int[] arr, int lo, int hi) {
    if(hi < lo) return null;
    int mid = (lo + hi) / 2;
    //TODO: fix indentation 2<< . to repeat
        Bst left = createBalancedBstHelper(arr, lo, mid-1);
        Bst right = createBalancedBstHelper(arr, mid+1, hi);
    return new Bst(arr[mid], left, right);
  }

  public boolean isBalanced() {
    //TODO add semi colons: A ;
    int leftHeight = (left == null) ? 0 : left.height()
    int rightHeight = (right == null) ? 0 : right.height()
    return Math.abs(left.height() - right.height()) <= 1;
  }

  public int height() {
    int leftHeight = (left == null) ? 0 : 1 + left.height();
    //TODO Fix the ordering: dd p
    return Math.max(leftHeight, rightHeight);
    int rightHeight = (right == null) ? 0 : 1 + right.height();
  }

  //rename to `root` `head`
  //TODO: :170, dt) b ciw head <esc> j 2f( l ciw head <esc> f( l ciw head <esc>
  public static boolean isBalanced(Bst root) {
    return Math.abs(height(root.left) - height(root.right)) <= 1;
  }

  public static int height(Bst root) {
    if(root == null) return 0;
    int leftHeight = 1 + height(root.left);
    int rightHeight = 1 + height(root.right);
    return Math.max(leftHeight, rightHeight);
  }

  public String toString() {
    StringBuffer buff = new StringBuffer();

    if(left != null) {
      buff.append(left);
    }

    buff.append(value);

    if(right != null) {
      buff.append(right);
    }

    return buff.toString();
  }

  public static void main(String[] args) {
    Bst balanced = new Bst(10,
        new Bst(5, null, null), new Bst(15, null, null));

    Bst unbalanced = new Bst(10,
        new Bst(5, null, null), new Bst(15, null, 
                                          new Bst(20, null, 
                                              new Bst(25, null, null))));

    System.out.println(String.format("balanced bst: %b", isBalanced(balanced)));
    System.out.println(String.format("unbalanced bst: %b", isBalanced(unbalanced)));
    System.out.println(String.format("balanced OOP bst: %b", balanced.isBalanced()));
    System.out.println(String.format("unbalanced OOP bst: %b", unbalanced.isBalanced()));

    Bst balancedBst = Bst.createBalancedBst(new int[] { 5, 4, 2, 3, 8 });
    System.out.println(balancedBst.toString());
    System.out.println(String.format("Balanced bst is balanced? %b", balancedBst.isBalanced()));
  }

}