Added solution for ProjectEuler/025: php, ruby

ProjectEuler/024/desc.yml

@@ -5,7 +5,8 @@ desc: |
   A permutation is an ordered arrangement of objects. For example, 3124 is one possible permutation of the digits 1, 2, 3 and 4. If all of the permutations are listed numerically or alphabetically, we call it lexicographic order. The lexicographic permutations of 0, 1 and 2 are:
   012   021   102   120   201   210
   What is the millionth lexicographic permutation of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9?
-todo: Improve algorithm - 
-solution: Bruteforce
 
-solutions:
+solutions:
+    solve.php:
+      desc: Basic Solution
+      language: php

ProjectEuler/024/solve.php

@@ -1,25 +1,26 @@
 <?php
-function fac($number) {
-	if($number == 1) 
-		return 1;
-	return $number * fac($number-1);
-}
-$result = array(0,0,0,0,0,0,0,0,0,0);
+define('NUM_PERMUTATION',1000000);
+define('DIGITS',9);
+$target = NUM_PERMUTATION - 1;
 
-$endsteps = 1000000;
-$cstep = 0;
-$cdigit = 9;
-while($cdigit != 0) {
-	
-	do{
-		$result[9-$cdigit]++;
-		$cstep += fac($cdigit);
-	} while ($cstep < $endsteps) ;
-	
-	echo "Done with $cdigit - steps:$cstep\n";
-	$cdigit--;
+$digits = range(0, 9);
+$permus = array(1 => 1);
+for ($i = 2; $i <= 9; $i++) {
+        $permus[$i] = $permus[$i - 1] * $i;
 }
-echo "DONE!";
-print_r($result);
-echo " - ".$cstep ."\n";
-echo "Result: 2783915460";
+$permus = array_reverse($permus);
+$values = array();
+
+foreach ($permus as $n) {
+        $values[] = floor($target / $n);
+        $target = $target%$n;
+}
+
+$result = "";
+foreach ($values as $val) {
+        $result .= $digits[$val];
+        unset($digits[$val]);
+        sort($digits);
+}
+$result .= $digits[0];
+echo $result;

ProjectEuler/025/desc.yml

@@ -0,0 +1,30 @@
+title: What is the first term in the Fibonacci sequence to contain 1000 digits?
+url: http://projecteuler.net/problem=25
+
+desc: |
+  The Fibonacci sequence is defined by the recurrence relation:
+
+  Fn = Fn1 + Fn2, where F1 = 1 and F2 = 1.
+  Hence the first 12 terms will be:
+
+  F1 = 1
+  F2 = 1
+  F3 = 2
+  F4 = 3
+  F5 = 5
+  F6 = 8
+  F7 = 13
+  F8 = 21
+  F9 = 34
+  F10 = 55
+  F11 = 89
+  F12 = 144
+  The 12th term, F12, is the first term to contain three digits.
+
+  What is the first term in the Fibonacci sequence to contain 1000 digits? 
+solution: Bruteforce
+
+solutions:
+  solve.php:
+    desc: Basic Solution
+    language: php

ProjectEuler/025/solve.php

@@ -0,0 +1,13 @@
+<?php
+define('DIGITS',1000);
+
+$current = 1;
+$prev = 1;
+$term = 2;
+while(strlen($current) < DIGITS) {
+	$term++;
+	$next = bcadd($current,$prev);
+	$prev = $current;
+	$current = $next;
+}
+echo $term;

ProjectEuler/025/solve.rb

@@ -0,0 +1,13 @@
+DIGITS = 1000
+
+max = 10 ** (DIGITS-1)
+fcurrent = 1
+fprev = 1
+term = 2
+while fcurrent < max do 
+	term = term + 1
+	fnext = fcurrent + fprev
+	fprev = fcurrent;
+	fcurrent = fnext;
+end
+puts term