kitgrose · January 9, 2014 06:38
diff --git a/balanced-columns.php b/balanced-columns.php
 <?php
 	/*
 		Makes n balanced lists of sub-lists, without breaking inside any existing lists.
 		
 		Expects input in the form:
 		
 		array(
 			'Section 1' => array(
 				'Item',
 				'Item',
 				...
 			),
 			'Section 2' => array(
 				...
 			),
 			...
 		)
 		
 		Returns output in the form:
 		
 		array(
 			0 => array(
 				'Section 1' => array(
 					'Item',
 					...
 				),
 				...
 			),
 			1 => array(
 				'Section 2' => array(
 					...
 				),
 				...
 			),
 			...
 		)
 	*/
 	
 	function generateRandomData($maxSections = 20, $maxItems = 20) {
 		$output = array();
 		for($i = 0; $i < rand(5, $maxSections); $i++) {
 			for($j = 0; $j < rand(1, $maxItems); $j++) {
 				$output['Section '.($i + 1)][] = 'Item '.($j + 1);
 			}
 		}
 		
 		return $output;
 	}
 	
 	function balanceList($fullList, $numColumns = 3) {
 		$totalListHeight = array_sum(array_map('count', $fullList)) + count($fullList); // Number of items plus number of sections to include headings
 		$idealColumnHeight = $totalListHeight / $numColumns;
 		
 		$output = array();
 		// Prime the column arrays so array_map can work
 		for($i = 0; $i < $numColumns; $i++) {
 			$output[$i] = array();
 		}
 		
 		$currentColumn = 0;
 		$listHeightRemaining = $totalListHeight;
 		foreach($fullList as $title => $section) {
 			$columnHeightWithSection = array_sum(array_map('count', $output[$currentColumn])) + count($section);
 			
 			if($columnHeightWithSection > $idealColumnHeight && $currentColumn !== $numColumns - 1) {
 				$overflow = $columnHeightWithSection - $idealColumnHeight;
 				
 				// If the overflow of inserting this item is less than the overflow that would be caused by letting it carry over, insert it
 				$expectedOverflowOnRemainingColumns = $listHeightRemaining / ($numColumns - $currentColumn - 1) - $idealColumnHeight;
 				
 				if($overflow > $expectedOverflowOnRemainingColumns) {
 					$currentColumn++;
 				}
 			}
 				
 			$output[$currentColumn][$title] = $section;
 			$listHeightRemaining -= count($section) + 1;
 		}

 		return $output;
 	}
 	
 	$numColumns = !empty($_REQUEST['cols']) ? intval($_REQUEST['cols']) : rand(3, 5);
 ?>
 <!DOCTYPE html>

 <html lang="en">
 	<head>
 		<meta charset="UTF-8" />

 		<style>
 			#columns {
 				display: table;
 				width: 100%;
 			}
 			
 			#columns div {
 				display: table-cell;
 				vertical-align: top;
 			}
 			
 			h1 {
 				font-size: 1em;
 			}
 		</style>
 	</head>
 	<body>
 		<div id="columns">
 <?php
 	foreach(balanceList(generateRandomData(), $numColumns) as $column) {
 ?>
 			<div class="column">
 <?php
 		foreach($column as $title => $section) {
 ?>
 				<h1><?php echo $title; ?></h1>
 				<ul>
 <?php
 			foreach($section as $item) {
 ?>
 					<li><?php echo $item; ?></li>
 <?php
 			}
 ?>
 				</ul>
 <?php
 		}
 ?>
 			</div>
 <?php
 	}
 ?>
 		</div>
 	</body>
 </html>
	<?php
	/*
	Makes n balanced lists of sub-lists, without breaking inside any existing lists.

	Expects input in the form:

	array(
	'Section 1' => array(
	'Item',
	'Item',
	...
	),
	'Section 2' => array(
	...
	),
	...
	)

	Returns output in the form:

	array(
	0 => array(
	'Section 1' => array(
	'Item',
	...
	),
	...
	),
	1 => array(
	'Section 2' => array(
	...
	),
	...
	),
	...
	)
	*/

	function generateRandomData($maxSections = 20, $maxItems = 20) {
	$output = array();
	for($i = 0; $i < rand(5, $maxSections); $i++) {
	for($j = 0; $j < rand(1, $maxItems); $j++) {
	$output['Section '.($i + 1)][] = 'Item '.($j + 1);
	}
	}

	return $output;
	}

	function balanceList($fullList, $numColumns = 3) {
	$totalListHeight = array_sum(array_map('count', $fullList)) + count($fullList); // Number of items plus number of sections to include headings
	$idealColumnHeight = $totalListHeight / $numColumns;

	$output = array();
	// Prime the column arrays so array_map can work
	for($i = 0; $i < $numColumns; $i++) {
	$output[$i] = array();
	}

	$currentColumn = 0;
	$listHeightRemaining = $totalListHeight;
	foreach($fullList as $title => $section) {
	$columnHeightWithSection = array_sum(array_map('count', $output[$currentColumn])) + count($section);

	if($columnHeightWithSection > $idealColumnHeight && $currentColumn !== $numColumns - 1) {
	$overflow = $columnHeightWithSection - $idealColumnHeight;

	// If the overflow of inserting this item is less than the overflow that would be caused by letting it carry over, insert it
	$expectedOverflowOnRemainingColumns = $listHeightRemaining / ($numColumns - $currentColumn - 1) - $idealColumnHeight;

	if($overflow > $expectedOverflowOnRemainingColumns) {
	$currentColumn++;
	}
	}

	$output[$currentColumn][$title] = $section;
	$listHeightRemaining -= count($section) + 1;
	}

	return $output;
	}

	$numColumns = !empty($_REQUEST['cols']) ? intval($_REQUEST['cols']) : rand(3, 5);
	?>
	<!DOCTYPE html>

	<html lang="en">
	<head>
	<meta charset="UTF-8" />

	<style>
	#columns {
	display: table;
	width: 100%;
	}

	#columns div {
	display: table-cell;
	vertical-align: top;
	}

	h1 {
	font-size: 1em;
	}
	</style>
	</head>
	<body>
	<div id="columns">
	<?php
	foreach(balanceList(generateRandomData(), $numColumns) as $column) {
	?>
	<div class="column">
	<?php
	foreach($column as $title => $section) {
	?>
	<h1><?php echo $title; ?></h1>
	<ul>
	<?php
	foreach($section as $item) {
	?>
	<li><?php echo $item; ?></li>
	<?php
	}
	?>
	</ul>
	<?php
	}
	?>
	</div>
	<?php
	}
	?>
	</div>
	</body>
	</html>