chu men zuo zhuan bian cheng ba

结果都是对的。。楼主用的O(n^(2/3))?

O(n^(2/3)) 会有误差的 我有的算法 没有误差

In 1985, Lagarias, Miller and Odlyzko [2] adapted the Meissel-Lehmer method
and proved that it is possible to compute pi(x) with O(x^(2/3)/log x) operations usingO(x^(1/3)log^2(x) log(log(x))) space.

They used their algorithm to compute several values of pi(x) up to x = 4*10^16

http://www.trnicely.net/pi/pix4.zip

http://arxiv.org/abs/1203.5712