-
Notifications
You must be signed in to change notification settings - Fork 0
/
008.lisp
32 lines (24 loc) · 1.94 KB
/
008.lisp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
(defun solve ()
(max-product-of-all-subsequences (number-to-digits (sample)) 5))
(defun sample ()
7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450)
(defun number-to-digits (n)
(if (< n 10)
(list n)
(cons (mod n 10) (number-to-digits (truncate n 10)))))
(defun max-product-of-all-subsequences (elems len)
(reduce #'max (max-products-of-all-subsequences elems len)))
(defun max-products-of-all-subsequences (elems len)
(mapcar #'(lambda (x) (max-product-of-subsequences x len)) (all-subsequences elems len)))
(defun all-subsequences (elems len)
(loop :for i :from 0 :below len :collect (nthcdr i elems)))
(defun max-product-of-subsequences (elems len)
(max-product-of-lists (split-list elems len)))
(defun max-product-of-lists (lists)
(reduce #'max (mapcar #'(lambda (x) (apply #'* x)) lists)))
(defun split-list (elems len)
(if (<= (length elems) len)
(list elems)
(let ((part (butlast elems (- (length elems) len)))
(rest (nthcdr len elems)))
(cons part (split-list rest len)))))