Initial data commit

Task/Periodic-table/PHP/periodic-table.php

@@ -0,0 +1,26 @@
+<?php
+// Periodic table
+
+class PeriodicTable
+{
+    private $aArray = array(1, 2, 5, 13, 57, 72, 89, 104);
+
+    private $bArray = array(-1, 15, 25, 35, 72, 21, 58, 7);
+
+    public function rowAndColumn($n)
+    {
+        $i = 7;
+        while ($this->aArray[$i] > $n)
+            $i--;
+        $m = $n + $this->bArray[$i];
+        return array(floor($m / 18) + 1, $m % 18 + 1);
+    }
+}
+
+$pt = new PeriodicTable();
+// Example elements (atomic numbers).
+foreach ([1, 2, 29, 42, 57, 58, 72, 89, 90, 103] as $n) {
+    list($r, $c) = $pt->rowAndColumn($n);
+    echo $n, " -> ", $r, " ", $c, PHP_EOL;
+}
+?>