2014-09-11

Problem 008: Largest product in a series

Description:

The four adjacent digits in the 1000-digit number that have the greatest product are 9 × 9 × 8 × 9 = 5832.

``...``

Find the thirteen adjacent digits in the 1000-digit number that have the greatest product. What is the value of this product?

Solution:
"v"00p54*:10p552**:20p*30p85+40p050p060p070p080p    v
>150g60p>60g:20g%\20g/9+g"0"-*60g1+:60p50g-40g-#v_:80g`#v_\$>50g1+:50p30g-#v_ 970p >70g0g86*+,70g8-40g-#v_"=",80g.@
^                                       <   \$      ^                                                       <
>80p060p>60g50g+:2 0g%\20g /9+g"0"-60g9+0p60g1+ :60p40g-#v_^
^                                                   <                     <       ^p07+1g07            <
^                                                <

73167176531330624919225119674426574742355349194934
96983520312774506326239578318016984801869478851843
85861560789112949495459501737958331952853208805511
12540698747158523863050715693290963295227443043557
66896648950445244523161731856403098711121722383113
62229893423380308135336276614282806444486645238749
30358907296290491560440772390713810515859307960866
70172427121883998797908792274921901699720888093776
65727333001053367881220235421809751254540594752243
52584907711670556013604839586446706324415722155397
53697817977846174064955149290862569321978468622482
83972241375657056057490261407972968652414535100474
82166370484403199890008895243450658541227588666881
16427171479924442928230863465674813919123162824586
17866458359124566529476545682848912883142607690042
24219022671055626321111109370544217506941658960408
07198403850962455444362981230987879927244284909188
84580156166097919133875499200524063689912560717606
05886116467109405077541002256983155200055935729725
71636269561882670428252483600823257530420752963450
Start
??
Pause
Reset
Output:
Stack:   (0)

Explanation:

These kinds of problems are fun in Befunge because you can just copy the input into your program and it becomes a part of your source code.

The rest is just walking through all possible values and printing the largest

 Interpreter steps: 614 295 Execution time (BefunExec): 234ms (2.63 MHz) Program size: 116 x 29 Solution: 23514624000 Solved at: 2014-09-11

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