Topswops: Difference between revisions

=={{header|Nim}}==

{{trans|Java}}

<lang nim>const maxBest = 32

var best: array[maxBest, int]

proc trySwaps(deck: seq[int], f, d, n: int) =

if d > best[n]:

best[n] = d

for i in countdown(n - 1, 0):

if deck[i] == -1 or deck[i] == i:

break

if d + best[i] <= best[n]:

return

var deck2 = deck

for i in 1..<n:

var k = 1 shl i

if deck2[i] == -1:

if (f and k) != 0:

continue

elif deck2[i] != i:

continue

deck2[0] = i

for j in countdown(i - 1, 0):

deck2[i - j] = deck[j]

trySwaps(deck2, f or k, d + 1, n)

proc topswops(n: int): int =

assert(n > 0 and n < maxBest)

best[n] = 0

var deck0 = newSeq[int](n + 1)

for i in 1..<n:

deck0[i] = -1

trySwaps(deck0, 1, 0, n)

best[n]

for i in 1..<11:

echo i, ": ", topswops(i)</lang>

{{out}}

<pre>

1: 0

2: 1

3: 2

4: 4

5: 7

6: 10

7: 16

8: 22

9: 30

10: 38

</pre>