From 0dc93ee0eee77c035d4b65f62bba480b95c6f25a Mon Sep 17 00:00:00 2001
From: FuryFire <furyfire@users.noreply.github.com>
Date: Fri, 9 Mar 2012 10:34:27 +0100
Subject: [PATCH] Solved ProjectEuler/015: php, ruby

---
 ProjectEuler/015/desc.yml  | 19 +++++++++++++++++++
 ProjectEuler/015/solve.php | 11 +++++++++++
 ProjectEuler/015/solve.rb  | 11 +++++++++++
 3 files changed, 41 insertions(+)
 create mode 100644 ProjectEuler/015/desc.yml
 create mode 100644 ProjectEuler/015/solve.php
 create mode 100644 ProjectEuler/015/solve.rb

diff --git a/ProjectEuler/015/desc.yml b/ProjectEuler/015/desc.yml
new file mode 100644
index 0000000..8e47a7c
--- /dev/null
+++ b/ProjectEuler/015/desc.yml
@@ -0,0 +1,19 @@
+title: Find the longest sequence using a starting number under one million.	
+url: http://projecteuler.net/problem=15
+
+desc: |
+  Starting in the top left corner of a 22 grid, there are 6 routes (without backtracking) to the bottom right corner.
+  How many routes are there through a 2020 grid?
+  
+solution: |
+  (2n)!/n!^2 - Where n is the size of the grid -
+  
+todo: Find a more "programmable way" instead of this cheating mathsolution
+
+solutions:
+  solve.php:
+    desc: Using BCMath to cope with large numbers
+    language: php
+  solve.rb:
+    desc: Basic solution
+    language: ruby
diff --git a/ProjectEuler/015/solve.php b/ProjectEuler/015/solve.php
new file mode 100644
index 0000000..e3eba6e
--- /dev/null
+++ b/ProjectEuler/015/solve.php
@@ -0,0 +1,11 @@
+<?php
+define('GRID_SIZE',20);
+function factorial($num) {
+	if($num == 0) 
+		return 1;
+	else 
+		return bcmul($num,factorial(bcsub($num,1)));
+}
+
+echo bcdiv(factorial(2* GRID_SIZE),bcpow(factorial( GRID_SIZE),2));
+
diff --git a/ProjectEuler/015/solve.rb b/ProjectEuler/015/solve.rb
new file mode 100644
index 0000000..ed6aed7
--- /dev/null
+++ b/ProjectEuler/015/solve.rb
@@ -0,0 +1,11 @@
+GRID_SIZE = 20
+
+def factorial(num) 
+	if(num == 0) 
+		return 1
+	else 
+		return num * factorial(num - 1)
+	end
+end
+
+puts factorial(2 * GRID_SIZE) / factorial(GRID_SIZE) ** 2
\ No newline at end of file