190. Reverse Bits

class Solution:
    # @param n, an integer
    # @return an integer
    def reverseBits(self, n):
        if not n:return 0
        res=0
        for i in range(32):
            res<<=1
            res+=n&1
            n>>=1
        return res 

class Solution:
    # @param n, an integer
    # @return an integer
    def reverseBits(self, n):
       return int('{:032b}'.format(n)[::-1],2)