RosettaCodeData/Task/Dice-game-probabilities/Python/dice-game-probabilities-3.py

25 lines
697 B
Python

from __future__ import division, print_function
from itertools import accumulate # Python3 only
def combos(sides, n):
ret = [1] + [0]*(n + 1)*sides # extra length for negative indices
for p in range(1, n + 1):
rolling_sum = 0
for i in range(p*sides, p - 1, -1):
rolling_sum += ret[i - sides] - ret[i]
ret[i] = rolling_sum
ret[p - 1] = 0
return ret
def winning(d1, n1, d2, n2):
c1, c2 = combos(d1, n1), combos(d2, n2)
ac = list(accumulate(c2 + [0]*(len(c1) - len(c2))))
return sum(v*a for v,a in zip(c1[1:], ac)) / (ac[-1]*sum(c1))
print(winning(4, 9, 6, 6))
print(winning(5, 10, 6, 7))
#print(winning(6, 700, 8, 540))