public function testLinkedList()
{
$list = new LinkedList();
$this->assertEquals(0, $list->getSize());
$this->assertTrue($list->isEmpty());
$this->assertNull($list->peekFirst());
$this->assertNull($list->peekLast());
$this->assertNull($list->removeFirst());
$this->assertNull($list->removeLast());
$count = 0;
foreach ($list as $key => $value) {
$count++;
}
$this->assertEquals(0, $count);
$list->add("one");
$this->assertEquals(1, $list->getSize());
$this->assertFalse($list->isEmpty());
$list->add("two");
$this->assertEquals(2, $list->getSize());
$this->assertFalse($list->isEmpty());
$list->add("three");
$this->assertEquals(3, $list->getSize());
$this->assertFalse($list->isEmpty());
$expected = ["one", "two", "three"];
$i = 0;
foreach ($list as $key => $value) {
$this->assertEquals($i, $key);
$this->assertEquals($expected[$i], $value);
$i++;
}
$this->assertEquals(3, $i);
$this->assertEquals("one", $list->peekFirst());
$this->assertEquals("one", $list->removeFirst());
$this->assertEquals(2, $list->getSize());
$this->assertEquals("three", $list->peekLast());
$this->assertEquals("three", $list->removeLast());
$this->assertEquals(1, $list->getSize());
$this->assertEquals("two", $list->peekFirst());
$this->assertEquals("two", $list->removeFirst());
$this->assertEquals(0, $list->getSize());
$this->assertTrue($list->isEmpty());
$list->add("four");
$this->assertEquals(1, $list->getSize());
$this->assertFalse($list->isEmpty());
foreach ($list as $key => $value) {
$this->assertEquals(0, $key);
$this->assertEquals("four", $value);
}
$this->assertEquals("four", $list->peekFirst());
$this->assertEquals("four", $list->removeLast());
$this->assertEquals(0, $list->getSize());
$this->assertTrue($list->isEmpty());
}
public static function getDepths(BinaryTreeNode $n)
{
$depths = [];
$nodes = new LinkedList();
$nodes->add($n);
while ($nodes !== null) {
$childNodes = new LinkedList();
foreach ($nodes as $node) {
$left = $node->getLeft();
if ($left !== null) {
$childNodes->add($left);
}
$right = $node->getRight();
if ($right !== null) {
$childNodes->add($right);
}
}
$depths[] = $nodes;
$nodes = !$childNodes->isEmpty() ? $childNodes : null;
}
return $depths;
}
