《Go语言圣经（中文版）》第二章 PopCount练习题

package popcount // pc[i] is the population count of i. var pc [256]byte func init() { for i := range pc { pc[i] = pc[i/2] + byte(i&1) } } // PopCount returns the population count (number of set bits) of x. func PopCount(x uint64) int { return int(pc[byte(x>>(0*8))] + pc[byte(x>>(1*8))] + p