PHP Taskbook Level 8.4

When a user enters a page, record the user's login time in the session. After refreshing the page, display the user's last login time on the screen.

Given some URL:

$url = 'http://test.com/dir1/dir2/dir3/page.html';

Get folders from it as an array:

['dir1', 'dir2', 'dir3']

Display the following pyramid on the screen:

1
22
333
4444
55555
666666
7777777
88888888
999999999

Given a list of cities and their countries, stored in the following structure:

<?php
	$data = [
		[
			'country' => 'country1',
			'city' =>    'city11',
		],
		[
			'country' => 'country2',
			'city' =>    'city21',
		],
		[
			'country' => 'country3',
			'city' =>    'city31',
		],
		[
			'country' => 'country1',
			'city' =>    'city12',
		],
		[
			'country' => 'country1',
			'city' =>    'city13',
		],
		[
			'country' => 'country2',
			'city' =>    'city22',
		],
		[
			'country' => 'country3',
			'city' =>    'city31',
		],
	];
?>

Write code that will remake the data structure into this:

[
	'country1': [
		'city11', 'city12', 'city13',
	],
	'country2': [
		'city21', 'city22'
	],
	'country3': [
		'city31', 'city32'
	],
]