from math import floor
def find_rotation(xs):
if xs[0] < xs[-1]:
return xs[0]
beg, end = 0, len(xs) - 1
found = False
count = 10
while not found and count >= 0:
i = beg + floor((end - beg) / 2)
if xs[beg] < xs[i]:
beg = i
i = beg + floor((end - beg) / 2)
elif xs[beg] > xs[i]:
end = i
found = xs[i - 1] > xs[i]
count -= 1
return xs[i]
xs = [(['ptolemaic',
'retrograde',
'supplant',
'undulate',
'xenoepist',
'zebra',
'asymptote',
'babka',
'banoffee',
'engender',
'karpatka',
'othellolagkage',
], "asymptote"),
(['asymptote',
'babka',
'banoffee',
'engender',
'karpatka',
'othellolagkage',
], "asymptote"),
]
for x, expected in xs:
result = find_rotation(x)
print(x, result)
assert result == expected
print("Success!")
