python计算圆周率pi
from sys import stdout  
  
scale = 10000  
maxarr = 2800  
arrinit = 2000  
carry = 0  
arr = [arrinit] * (maxarr + 1)  
for i in xrange(maxarr, 1, -14):  
    total = 0  
    for j in xrange(i, 0, -1):  
        total = (total * j) + (scale * arr[j])  
        arr[j] = total % ((j * 2) - 1)  
        total = total / ((j * 2) - 1)  
    stdout.write("%04d" % (carry + (total / scale)))  
    carry = total % scale  
