Solutions to Challenges 1, 2, and 4

Challenge 1 - Sorting/challenge1.php

@@ -1,2 +1,42 @@
 <?php
 
+
+class ArraySort
+{
+  public function sort(array $arr)
+  {
+    $n = sizeof($arr);
+    for ($i = 0; $i < $n; $i++) {
+      for ($j = $n-1; $j > $i; $j-- ) {
+        if ($arr[$j-1] > $arr[$j]) {
+          $arr = $this->swap($j-1, $j, $arr);
+        }
+      }
+    }
+    return $arr;
+  }
+
+  public function swap($i, $j, array $arr)
+  {
+    $tmp = $arr[$i];
+    $arr[$i] = $arr[$j];
+    $arr[$j] = $tmp;
+
+    return $arr;
+  }
+}
+
+$rand_arr = array();
+
+for ($i = 0; $i < 100; $i++) {
+    array_push($rand_arr, rand (1, 99));
+}
+
+echo nl2br("Original Array:\n");
+print_r($rand_arr);
+
+$sorter = new ArraySort;
+echo nl2br("\n\nSorted Array:\n");
+print_r($sorter->sort($rand_arr));
+
+?>

Challenge 2 - Uppercase/challenge2.php

@@ -1,2 +1,4 @@
 <?php
+echo preg_replace_callback('/\b(\w)/', function ($match) { return strtoupper($match[0]);} , 'in-touch insight systems inc. programming challenge number 2');
 
+?>

Challenge 4 - 3n+1/Cycle.php

@@ -0,0 +1,66 @@
+<?php
+
+class Cycle
+{
+  private $cycle_length_map = array();
+
+  public function findMaxCycleLengthBetween($a, $b) {
+    $max_cycle  = array(array(0), 0);
+    $i = min($a, $b);
+    $j = max($a, $b);
+    while($i <= $j) {
+      $length = $this->findCycleLength($i);
+      $current_max_length = $max_cycle[1];
+      if ($current_max_length < $length) {
+        $max_cycle = array(array($i), $length);
+      } elseif ($current_max_length == $length) {
+        array_push($max_cycle[0], $i);
+      }
+      $i++;
+    }
+    return $max_cycle;
+  }
+
+  public function findCycleLength($n)
+  {
+    if ($n == 1) {
+      $this->cycle_length_map[$n] = 1;
+    }
+    if (!isset($this->cycle_length_map[$n])) {
+      $length = 1 + $this->findCycleLength($this->nextNumberAfter($n));
+      $this->cycle_length_map[$n] = $length;
+    }
+    return $this->cycle_length_map[$n];
+  }
+
+  public function generateCycle($n)
+  {
+    $cycle_array = array();
+    array_push($cycle_array, $n);
+
+    $count = 0;
+
+    $i = $n;
+    while($i != 1) {
+      $next = $this->nextNumberAfter($i);
+      array_push($cycle_array, $next);
+      $i = $next;
+
+      $count++;
+    }
+    return $cycle_array;
+  }
+
+  public function nextNumberAfter($n)
+  {
+    if ($n%2 == 0) {
+      return $n/2;
+    } else {
+      return (3 * $n) + 1;
+    }
+  }
+
+}
+
+
+?>

Challenge 4 - 3n+1/CycleTest.php

@@ -0,0 +1,39 @@
+<?php
+include_once('cycle.php');
+
+class CycleTest extends PHPUnit_Framework_TestCase
+{
+    public function testNextNumber()
+    {
+        $cycle = new Cycle;
+        $this->assertEquals(4, $cycle->nextNumberAfter(8));
+        $this->assertEquals(16, $cycle->nextNumberAfter(5));
+        $this->assertEquals(1, $cycle->nextNumberAfter(2));
+        $this->assertEquals(4, $cycle->nextNumberAfter(1));
+    }
+
+    public function testCycleGeneration()
+    {
+        $cycle = new Cycle;
+        $this->assertEquals(array(22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1), $cycle->generateCycle(22));
+    }
+
+    public function testCycleLength()
+    {
+        $cycle = new Cycle;
+        $this->assertEquals(1, $cycle->findCycleLength(1));
+        $this->assertEquals(2, $cycle->findCycleLength(2));
+        $this->assertEquals(16, $cycle->findCycleLength(22));
+    }
+
+    public function testMaxCycleLength()
+    {
+        $cycle = new Cycle;
+        $this->assertEquals(array(array(1), 1), $cycle->findMaxCycleLengthBetween(1, 1));
+        $this->assertEquals(array(array(9), 20), $cycle->findMaxCycleLengthBetween(16, 1));
+        $this->assertEquals(array(array(18, 19), 21), $cycle->findMaxCycleLengthBetween(1, 22));
+        $this->assertEquals(array(array(999999), 259), $cycle->findMaxCycleLengthBetween(999999, 1000000));
+    }
+}
+?>
+

Challenge 4 - 3n+1/challenge4.php

@@ -0,0 +1,27 @@
+<?php
+include 'cycle.php';
+
+function check_within_bounds($input) {
+  return ($input <= 0) || ($input > 1000000);
+}
+
+$i = intval($_GET['i']);
+$j = intval($_GET['j']);
+
+if (check_within_bounds($i) && check_within_bounds($i)) {
+  echo "Inputs must be between 1 and 1000000";
+} else {
+  $cycle = new Cycle;
+  $max_length_array = $cycle->findMaxCycleLengthBetween($i, $j);
+  echo nl2br("Inputs: $i, $j");
+
+  echo nl2br("\nNumber(s) with highest cycle length: ");
+  echo implode(", ", $max_length_array[0]);
+
+  echo nl2br("\nHighest cycle length: ");
+  echo $max_length_array[1];
+
+
+}
+
+?>