Project Euler Problem 28

これは、図を見てえいやっと考えれば簡単。

#!/usr/bin/python

EDGE_MAX = 1001
a,b,c,d = 3,5,7,9
s = 1
diff = 10
while b-a+1 <= EDGE_MAX:
    s += a + b + c + d
    edge = b - a + 2
    a += diff
    diff += 8
    b = a + edge
    c = b + edge
    d = c + edge

print s