Data commit

Task/Ascending-primes/PHP/ascending-primes.php

@@ -0,0 +1,36 @@
+<?php
+
+function isPrime($n)
+{
+    if ($n == 2)
+        return true;
+    if ($n == 1 || $n % 2 == 0)
+        return false;
+    $root = intval(sqrt($n));
+    for ($k = 3; $k <= $root; $k += 2)
+        if ($n % $k == 0)
+            return false;
+    return true;
+}
+
+$queue = [];
+$primes = [];
+
+$begin = 0;
+$end = 0;
+
+for ($k = 1; $k <= 9; $k++)
+    $queue[$end++] = $k;
+
+while ($begin < $end)
+{
+    $n = $queue[$begin++];
+
+    if (isPrime($n))
+        $primes[] = $n;
+    for ($k = $n % 10 + 1; $k <= 9; $k++)
+        $queue[$end++] = $n * 10 + $k;
+}
+
+foreach($primes as $p)
+    echo "$p ";