def f1(n):
"""Single digit ms. O(terrible)"""
low = 10**(n - 1) - 1
hi = 10**n - 1
best = 0
for x in range(hi, low, -1):
for y in range(x, low, -1):
prod = x*y
if prod < best:
# if prod < best when y is hi, we are done
# if y is smaller, maybe a new x will work better
if y == x:
return best
else:
break
if is_palin(prod):
if prod > best:
best = prod
def f(n):
return sum([a for a in range(n) if is_palin(a) and is_bin_palin(a)])
def f0(n):
"""Nearly a second for 3"""
rng = range(10**(n - 1), 10**n)
return max([x*y for x in rng for y in rng if is_palin(x*y)])