Help with Script

[youngdesigner]

Good evening,

I am trying to figure out how to make the following possible.

I have 8 rooms and 50 people labeled as such:

H3, A1, S1, R4, I2, T1, C2, K1, V2, E2, W2, S2, P1, V1, N1, Q1, R3, C3, M2, W3, E1, L2, D1, X2, L3, R2, G1, H2, U1, M1, Q2, N2, U2, L1, J1, I1, R1, Q3, J2, T2, E3, X1, W4, W1, C1, P2, I3, A2, B1, and H1.

What I am trying to do is to randomly place these 50 people into 8 different rooms (with a max of 7 in each room). The trick is to try not having the same letter in the same room. Would any of you be able to help me with this? I have attached a picture of what I am trying to attain.

I have been wrapping my brain around this idea all day, and cannot find a way to begin. I know this is possible, but I have no idea. I look forward to hearing your responses.

[NogDog]

There's probably a more elegant way, but here's what I came up with. (I'll leave it to you to output the $assignments array in the desired HTML format or whatever you want.)

<?php
$people = array('H3', 'A1', 'S1', 'R4', 'I2', 'T1', 'C2', 'K1', 'V2', 'E2',
                'W2', 'S2', 'P1', 'V1', 'N1', 'Q1', 'R3', 'C3', 'M2', 'W3',
                'E1', 'L2', 'D1', 'X2', 'L3', 'R2', 'G1', 'H2', 'U1', 'M1',
                'Q2', 'N2', 'U2', 'L1', 'J1', 'I1', 'R1', 'Q3', 'J2', 'T2',
                'E3', 'X1', 'W4', 'W1', 'C1', 'P2', 'I3', 'A2', 'B1', 'H1');
$letterGroups = array();
foreach($people as $person) {
    $letterGroups[substr($person, 0, 1)][] = $person;
}
$rooms = range(1,8);
$assignments = array();
foreach($letterGroups as $group) {
    shuffle($rooms);
    shuffle($group);
    foreach($rooms as $room) {
        if( ! isset($assignments[$room]) or count($assignments[$room]) < 7) {
            $assignments[$room][] = array_pop($group);
            if(count($group) == 0) {
                break;
            }
        }
    }
}
ksort($assignments);
echo "<pre>".print_r($assignments, true)."</pre>";

[youngdesigner]

Thank you for the script above - it is working magically. How would I be able to then set a limiter, saying that yes, no more than 7 people in a room, but no less than 5?

[NogDog]

That sounds a bit messier. Maybe after getting to that point, you'd then have to come up with a routine to look for sub-arrays with less than 5 elements, and if you find one, randomly choose one of the sub-arrays with more than 5 elements and "move" one of its members to the underpopulated array?