Reverse Bits

Reverse bits of a given 32 bits unsigned integer.

Note:

• In some languages, such as Java, there is no unsigned integer type. In this case, both input and output will be given as a signed integer type. They should not affect your implementation, as the integer's internal binary representation is the same, whether it is signed or unsigned.
• In Java, the compiler represents the signed integers using 2's complement notation. Therefore, in Example 2, the input represents the signed integer -3 and the output represents the signed integer -1073741825.