Cantor pairing functions in PHP. Pass any two positive integers and get a unique integer back. Feed the unique integer back into the reverse function and get the original integers back. Explanation and JS implementation here: http://stevegardner.net/2012/07/09/javascript-cantor-pairing-function-and-reverse-function/

cantor_pairing.php

<?php

/**
 * Calculate a unique integer based on two integers (cantor pairing).
 */
function cantor_pair_calculate($x, $y) {
  return (($x + $y) * ($x + $y + 1)) / 2 + $y;
}
 
/**
 * Return the source integers from a cantor pair integer.
 */
function cantor_pair_reverse($z) {
  $t = floor((-1 + sqrt(1 + 8 * $z))/2);
  $x = $t * ($t + 3) / 2 - $z;
  $y = $z - $t * ($t + 1) / 2;
  return array($x, $y);
}

thanks! :D

NICE THX

SWEET

Uh, should it not be ((x+y)*(x+y+1)+y)*0.5 ?

Uh, should it not be ((x+y)*(x+y+1)+y)*0.5 ?

Not according to Wikipedia.