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.
class Solution { public: int rangeBitwiseAnd(int m, int n) { int d = 0; while(m!=n){ m >>= 1 ; n >>= 1 ; d++; } return m<<d; } };
原文：http://www.cnblogs.com/zengzy/p/5052753.html