49 lines
1.1 KiB
Python
49 lines
1.1 KiB
Python
#!/usr/bin/env python
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"""
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Created on 3 Jan 2020
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@author: David Doblas Jiménez
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@email: daviddoji@pm.me
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Solution for problem 028 of Project Euler
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https://projecteuler.net/problem=28
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"""
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from utils import timeit
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@timeit("Problem 028")
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def compute():
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"""
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Starting with the number 1 and moving to the right in a clockwise
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direction a 5 by 5 spiral is formed as follows:
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21 22 23 24 25
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20 7 8 9 10
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19 6 1 2 11
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18 5 4 3 12
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17 16 15 14 13
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It can be verified that the sum of the numbers on the diagonals is 101.
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What is the sum of the numbers on the diagonals in a 1001 by 1001 spiral
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formed in the same way?
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"""
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size = 1001 # Must be odd
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ans = 1 # Special case for size 1
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step = 0
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i, current = 1, 1
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while step < size - 1:
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step = i * 2
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for _ in range(1, 5):
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current += step
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ans += current
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i += 1
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return ans
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if __name__ == "__main__":
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print(f"Result for Problem 028: {compute()}")
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