Starting with the number 1 and moving to the right in a clockwise direction a 5 by 5 spiral is formed as follows:
21 22 23 24 25
20 7 8 9 10
19 6 1 2 11
18 5 4 3 12
17 16 15 14 13
It can be verified that the sum of the numbers on the diagonals is 101.
What is the sum of the numbers on the diagonals in a 1001 by 1001 spiral formed in the same way?
import time begin = time.time() n = 1001 num = n*n resu = 0 count = n-1 while num != 1: resu += 4*num-6*count num = num - 4*count count -= 2 print resu+1 end = time.time() print end-begin
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projecteuler---->problem=28----Number spiral diagonals
原文地址:http://blog.csdn.net/q745401990/article/details/38708827