題目

Given a range [m, n] where 0 <= m <= n <= 2147483647, return the bitwise AND of all numbers in this range, inclusive.
Example 1:
Input: [5,7]
Output: 4
Example 2:
Input: [0,1]
Output: 0

思路

參考這個：http://www.cnblogs.com/grandyang/p/4431646.html

實現程式碼

class Solution(object):
    def
 
 rangeBitwiseAnd(self, m, n):
        """
        :type m: int
        :type n: int
        :rtype: int
        """
        i = 0
        while m != n:
            m = m >> 1
            n = n >> 1
            i += 1
        return m << i