Python/project_euler/problem_115/sol1.py

63 lines
1.8 KiB
Python
Raw Normal View History

"""
Project Euler Problem 115: https://projecteuler.net/problem=115
NOTE: This is a more difficult version of Problem 114
(https://projecteuler.net/problem=114).
A row measuring n units in length has red blocks
with a minimum length of m units placed on it, such that any two red blocks
(which are allowed to be different lengths) are separated by at least one black square.
Let the fill-count function, F(m, n),
represent the number of ways that a row can be filled.
For example, F(3, 29) = 673135 and F(3, 30) = 1089155.
That is, for m = 3, it can be seen that n = 30 is the smallest value
for which the fill-count function first exceeds one million.
In the same way, for m = 10, it can be verified that
F(10, 56) = 880711 and F(10, 57) = 1148904, so n = 57 is the least value
for which the fill-count function first exceeds one million.
For m = 50, find the least value of n
for which the fill-count function first exceeds one million.
"""
from itertools import count
def solution(min_block_length: int = 50) -> int:
"""
Returns for given minimum block length the least value of n
for which the fill-count function first exceeds one million
>>> solution(3)
30
>>> solution(10)
57
"""
fill_count_functions = [1] * min_block_length
for n in count(min_block_length):
fill_count_functions.append(1)
for block_length in range(min_block_length, n + 1):
for block_start in range(n - block_length):
fill_count_functions[n] += fill_count_functions[
n - block_start - block_length - 1
]
fill_count_functions[n] += 1
if fill_count_functions[n] > 1_000_000:
break
return n
if __name__ == "__main__":
print(f"{solution() = }")