Merge pull request #2915 from ash/master

Week 89 Task 1 and an Advent blog post

1 files changed, 27 insertions, 0 deletions

diff --git a/challenge-089/ash/php/ch-1.php b/challenge-089/ash/php/ch-1.php
new file mode 100644
index 0000000000..9209076d61
--- /dev/null
+++ b/challenge-089/ash/php/ch-1.php
@@ -0,0 +1,27 @@
+<?php
+    // Run as:
+    // $ php ch-1.php 100
+    // 13015
+
+    function gcd($a, $b) {
+        while ($b) {
+            $t = $b;
+            $b = $a % $b;
+            $a = $t;
+        }
+
+        return $a;
+    }
+
+    $n = $argc == 2 ? $argv[1] : 3;
+
+    $s = 0;
+    for ($x = 1; $x <= $n; $x++) {
+        for ($y = $x + 1; $y <= $n; $y++) {
+            $s += gcd($x, $y);
+        }
+    }
+
+    echo "$s\n";
+
+?>