小编use*_*552的帖子

以下两个C函数是等效的:

unsigned f(unsigned A, unsigned B) {
  return (A | B) & -(A | B);
}
unsigned g(unsigned A, unsigned B) {
  unsigned C = (A - 1) & (B - 1);
  return (C + 1) & ~C;
}

我的问题是:为什么它们相同？将g它转化为什么规则/变换f？