From ce2fde09a034f487cfca52dabb4eed15845f3770 Mon Sep 17 00:00:00 2001
From: somethingweird <somethingweird@yahoo.com>
Date: Tue, 1 Dec 2020 10:29:41 -0500
Subject: C89

---
 challenge-089/henry-wong/php/ch-1.php | 24 ++++++++++++++++
 challenge-089/henry-wong/php/ch-2.php | 54 +++++++++++++++++++++++++++++++++++
 2 files changed, 78 insertions(+)
 create mode 100644 challenge-089/henry-wong/php/ch-1.php
 create mode 100644 challenge-089/henry-wong/php/ch-2.php

diff --git a/challenge-089/henry-wong/php/ch-1.php b/challenge-089/henry-wong/php/ch-1.php
new file mode 100644
index 0000000000..4303a961b3
--- /dev/null
+++ b/challenge-089/henry-wong/php/ch-1.php
@@ -0,0 +1,24 @@
+<?php
+
+function gcd($a, $b) {
+    // could of used https://www.php.net/manual/en/function.gmp-gcd.php
+    return ($a % $b) ? gcd($b,$a % $b) : $b;
+}
+function solutions($N) {
+    // $N can't be less than 2
+    if ($N <= 1) {
+        return false;
+    }
+    $total = 0;
+    for ($i = 1; $i <= $N; $i++) {        
+        for ($next = $i + 1; $next <= $N; $next++) {
+            // debug purpose
+            printf ("gcd(%s, %s)\n", $i, $next);
+            $total += gcd($i, $next);
+        }        
+    }
+    return $total;
+}
+
+echo solutions(3), "\n";
+echo solutions(4), "\n";
\ No newline at end of file
diff --git a/challenge-089/henry-wong/php/ch-2.php b/challenge-089/henry-wong/php/ch-2.php
new file mode 100644
index 0000000000..41146f3a13
--- /dev/null
+++ b/challenge-089/henry-wong/php/ch-2.php
@@ -0,0 +1,54 @@
+<?php
+
+/**
+There are two rules for constructing an odd magic square 
+1. "top right" 
+2. "if the place is occupied, go one down"
+**/
+
+function solution($N) {
+    if ($N % 2 == 0) {
+        // I only know how to solve odd size magic squares for now.
+        // I'll have figure out even magic squares later.
+       return false;
+    }
+    $board = [];
+    $numbers = $N * $N;
+    for ($i = 1 ; $i <= $numbers; $i++) {
+        if ($i == 1) {
+            // top middle
+            $y = 0;
+            $x = ((int)($N / 2));  # would have add +1 but we starting with base 0
+            $board[$y][$x] = $i;
+            
+        } else {
+            // check if top right is empty
+            $y-=1;
+            $x+=1;
+            $sy = $y < 0 ? $N - 1 : $y;
+            $sx = $x >= $N ? 0 : $x;
+            if (! isset($board[$sy][$sx])) {
+                 // if empty - then assign number
+                $board[$sy][$sx] = $i; 
+                $y = $sy;
+                $x = $sx;
+            } else {
+                // else go down a row.                
+                $x-=1;
+                $y+=2;
+                $board[$y][$x] = $i;
+                
+            }           
+        }
+    }
+    // clean up sort the key correctly
+    
+    for($i = 0; $i < $N; $i++) {
+        ksort($board[$i]);
+    };
+    ksort($board);
+    return $board;
+}
+
+print_r(solution(3)); // 3x3
+print_r(solution(5)); // 5x5
\ No newline at end of file
-- 
cgit