Generates a numeric pyramid based on a string or a sequence of numbers

triangle.php

<?
	set_time_limit(120);
	error_reporting(E_ALL ^ E_NOTICE);
	
	$in = $_GET["in"];
	//$op = $_GET["op"] == 1 ? 1 : 0;
		
	$in = $_GET["mode"] == "rnd()" ? rand(1, str_repeat("9", rand(2,9))) : $in;
	
	$num = explode(" ", $in);
	$trace = $_GET["trace"];

	echo "<center><font face='Courier New'>
			  <form action='?'>
			  <input type='text' name='in' value='{$in}'><br>
			  <!-- <input type='radio' name='op' value='0' checked='checked'>+
			  <input type='radio' name='op' value='1'>*<br>-->
			  <input type='checkbox' name='mode' value='rnd()'>Rnd()
			  <input type='checkbox' name='trace' value='1'>Trace
			  <input type='submit' name='mode' value='' style='visibility:hidden'><br>
			  </form>
		  </center>";

	flush();

	foreach ($num as $in) {
		$res = array();
	
		if (!preg_match("/[0-9]/", $in)) {
			$in = strtolower($in);
			$in = preg_replace("/[^a-z]/", "", $in);
			$in = correspondentes($in);			
		}

		$tri = triangulo($in, 0, $op);	
		
		echo("<center><div style='letter-spacing:20px;'>");
		
		foreach ($tri as $ln) 
			echo "$ln<br>";

		echo "</div></center>";

		flush();		  

		if ($trace) {
			echo("<pre>");

			foreach($tri as $ln) {
				$tra = todos($ln);
				
				foreach($tra as $lna)
					$res[$ln][] = $lna . (in_array($lna, $tri)
					                      ? " +"
										  : (strpos($lna, "0") > 0
										     ? " -"
											 : ""));	
					
				//if ($i++ == count($lna) + 1) break;
			}	

			print_r($res);

			echo("</pre>");
		}

		echo("<hr>");
	}

	// ------------------------------------------------------------------------------------------------------------------------
	// ------------------------------------------------------------------------------------------------------------------------
	// ------------------------------------------------------------------------------------------------------------------------
	
	function triangulo($x, $n = 0) {
		$ope = $op == 1 ? "*" : "+";
		$z[] = $x;

		while ($x > 9) {
			$y = "";
			$s = strlen($x) - 1;
			$x = (string) $x;
			
			while($s--) {
				$e = $x{$s + 1} + $x{$s};
				$y .= $e < 10 ? $e : triangulo($e, 1);
			}
		
			$z[] = $x = strrev($y);
		}

		return $n ? $z[1] : array_reverse($z);
	}
	
	function correspondentes($s) {
		$x = "";
		$y = strlen($s);
		
		while ($y--)
			$x .= ord(substr($s, $y, 1)) - 96; 

		return strrev($x);
	}

	function todos($prova) {
		$base = strlen($prova) + 1;
		$off = $base - 2;
		
		$ini = str_repeat(1, $base);
		$fim = str_repeat(9, $base);
	
		for ($i = $ini; $i <= $fim; $i++) {
			$tri = triangulo($i);
			$res = $tri[$off];
			
			// if (/*!strpos($i, "0") && !($i % 10 == 0) &&*/ $res == $prova)
			if ($res == $prova)
				$x[] = $i;
		}
		
		return $x;
	}	
	
?>