Skip to content

Instantly share code, notes, and snippets.

@pmgupte
Last active December 28, 2015 18:09
Show Gist options
  • Select an option

  • Save pmgupte/7541378 to your computer and use it in GitHub Desktop.

Select an option

Save pmgupte/7541378 to your computer and use it in GitHub Desktop.
PHP solution to Project Euler problem # 8.
<?php
/*
* Problem 8: Largest product in a series
* Find the greatest product of five consecutive digits in the 1000-digit number:
* 73167176531330624919225119674426574742355349194934
* 96983520312774506326239578318016984801869478851843
* 85861560789112949495459501737958331952853208805511
* 12540698747158523863050715693290963295227443043557
* 66896648950445244523161731856403098711121722383113
* 62229893423380308135336276614282806444486645238749
* 30358907296290491560440772390713810515859307960866
* 70172427121883998797908792274921901699720888093776
* 65727333001053367881220235421809751254540594752243
* 52584907711670556013604839586446706324415722155397
* 53697817977846174064955149290862569321978468622482
* 83972241375657056057490261407972968652414535100474
* 82166370484403199890008895243450658541227588666881
* 16427171479924442928230863465674813919123162824586
* 17866458359124566529476545682848912883142607690042
* 24219022671055626321111109370544217506941658960408
* 07198403850962455444362981230987879927244284909188
* 84580156166097919133875499200524063689912560717606
* 05886116467109405077541002256983155200055935729725
* 71636269561882670428252483600823257530420752963450
*/
$number = '73167176531330624919225119674426574742355349194934
96983520312774506326239578318016984801869478851843
85861560789112949495459501737958331952853208805511
12540698747158523863050715693290963295227443043557
66896648950445244523161731856403098711121722383113
62229893423380308135336276614282806444486645238749
30358907296290491560440772390713810515859307960866
70172427121883998797908792274921901699720888093776
65727333001053367881220235421809751254540594752243
52584907711670556013604839586446706324415722155397
53697817977846174064955149290862569321978468622482
83972241375657056057490261407972968652414535100474
82166370484403199890008895243450658541227588666881
16427171479924442928230863465674813919123162824586
17866458359124566529476545682848912883142607690042
24219022671055626321111109370544217506941658960408
07198403850962455444362981230987879927244284909188
84580156166097919133875499200524063689912560717606
05886116467109405077541002256983155200055935729725
71636269561882670428252483600823257530420752963450';
$largest_product = 1;
for($i=0; $i<strlen($number); $i++) {
$arr = str_split(substr($number, $i, 5));
$product = 1;
foreach($arr as $a) { $product *= $a; }
if($product > $largest_product) { $largest_product = $product; }
}
echo "Largest product of 5 consecutive digits = $largest_product";
?>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment