Answer for http://stackoverflow.com/q/14209509

so-14209509.php

<?php

// quick and dirty color generator
function getColors($count) {
    $colors = array();

    for ($i = 0; $i < $count; $i++) {
        $colors[] = '#' . substr(md5("color$i"), 0, 6);
    }

    return $colors;
}

// names
$names = array(
    array('sanitized' => 'lisa',  'original' => 'Lisa',  'weight' => 5, 'color' => 'blank'),
    array('sanitized' => 'jack',  'original' => 'Jack',  'weight' => 1, 'color' => 'blank'),
    array('sanitized' => 'jerry', 'original' => 'Jerry', 'weight' => 2, 'color' => 'blank'),
    array('sanitized' => 'paul',  'original' => 'Paul',  'weight' => 4, 'color' => 'blank'),
    array('sanitized' => 'ron',   'original' => 'Ron',   'weight' => 2, 'color' => 'blank'),
    array('sanitized' => 'harry', 'original' => 'Harry', 'weight' => 3, 'color' => 'blank'),
    array('sanitized' => 'mike',  'original' => 'Mike',  'weight' => 4, 'color' => 'blank'),
    array('sanitized' => 'lisa',  'original' => 'Lisa',  'weight' => 3, 'color' => 'blank'),
    array('sanitized' => 'ron',   'original' => 'Ron',   'weight' => 5, 'color' => 'blank'),
    array('sanitized' => 'dylan', 'original' => 'Dylan', 'weight' => 1, 'color' => 'blank'),
);

$colors = getColors(count($names));
$combined = array();

// loop once to build the combined array and set the colors
foreach ($names as &$name) {
    if (!isset($combined[$name['sanitized']])) {
        $combined[$name['sanitized']] = array(
            'original' => $name['original'],
            'weight'   => $name['weight'],
            'color'    => array_pop($colors),
            'count'    => 1,
        );
    } elseif ($combined[$name['sanitized']]['count'] < 3) {
        $combined[$name['sanitized']]['weight'] += $name['weight'];
        $combined[$name['sanitized']]['count']++;
    }

    $name['color'] = $combined[$name['sanitized']]['color'];
}


// loop again to blank any colors where name only appeared once
foreach ($names as &$name) {
    if ($combined[$name['sanitized']]['count'] === 1) {
        $combined[$name['sanitized']]['color'] = $name['color'] = 'blank';
    }
}

var_dump($combined, $names);