bitwise and of range
题目描述
Given a range [m, n] where 0 <= m <= n <= 2147483647, return the bitwise AND of all numbers in this range, inclusive.
For example, given the range [5, 7], you should return 4.
解题方法
去掉都是不同的bit，找到所有数左边的共同部分，其实也就是最大值和最小值左边的共同部分