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33 lines (30 loc) · 828 Bytes
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l10_flags.py
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33 lines (30 loc) · 828 Bytes
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from math import sqrt
def transform(A):
peak_pos = len(A)
last_height = A[-1]
for p in range(len(A) - 1, 0, -1):
if (A[p - 1] < A[p] > last_height):
peak_pos = p
last_height = A[p]
A[p] = peak_pos
A[0] = peak_pos
def can_fit_flags(A, k):
flag = 1 - k
for i in range(k):
# plant the next flag at A[flag + k]
if flag + k > len(A) - 1:
return False
flag = A[flag + k]
return flag < len(A) # last flag planted successfully
def solution(A):
transform(A)
lower = 0
upper = int(sqrt(len(A))) + 2
assert not can_fit_flags(A, k=upper)
while lower < upper - 1:
next = (lower + upper) // 2
if can_fit_flags(A, k=next):
lower = next
else:
upper = next
return lower