Product of Consecutive digits.April 23, 2007Problem number 8 on project Euler is the easiest of the 150 problems listed there. Your don't really need any code to solve it. You can just to a simple text search and come up with the answer. In case you are too lazy to do that. Here is the solution:
$str="73167176531330624919225119674426574742355349194934".
"96983520312774506326239578318016984801869478851843".
"85861560789112949495459501737958331952853208805511".
"12540698747158523863050715693290963295227443043557".
"66896648950445244523161731856403098711121722383113".
"62229893423380308135336276614282806444486645238749".
"30358907296290491560440772390713810515859307960866".
"70172427121883998797908792274921901699720888093776".
"65727333001053367881220235421809751254540594752243".
"52584907711670556013604839586446706324415722155397".
"53697817977846174064955149290862569321978468622482".
"83972241375657056057490261407972968652414535100474".
"82166370484403199890008895243450658541227588666881".
"16427171479924442928230863465674813919123162824586".
"17866458359124566529476545682848912883142607690042".
"24219022671055626321111109370544217506941658960408".
"07198403850962455444362981230987879927244284909188".
"84580156166097919133875499200524063689912560717606".
"05886116467109405077541002256983155200055935729725".
"71636269561882670428252483600823257530420752963450";
echo strlen($str) . "\n";
$max =0;
for($I=0; $i < 1000; $i++)
{
$a1 = (int)substr($str,$i,1);
$a2 = (int)substr($str,$i+1,1);
$a3 = (int)substr($str,$i+2,1);
$a4 = (int)substr($str,$i+3,1);
$a5 = (int)substr($str,$i+4,1);
$product = $a1*$a2*$a3*$a4*$a5;
// echo "$a1 $a2 $a3 $a4 $a5\n";
if($max < $product) {
$max = $product;
echo "New max = $max\n";
}
}
echo $max;
|
|
