190_reverseBits 🌟

Reverse bits of a given 32 bits unsigned integer.

Note:

• Note that 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 above, the input represents the signed integer -3 and the output represents the signed integer -1073741825.

Using lsb

• n&1 will give us lsb.
• we will shift lsb to left by 31-i bits and it will be our reverseLsb.
• we will or reverseLsb with result.
• shift n by 1 to right.
• Reference Video

Code

class Solution{
public:
	uint32_t reverseBits(uint32_t n){
		int res = 0;
		for (int i = 0; i < 32; i++){
			int lsb = n & 1;
			int reverseLsb = lsb << (31 - i);
			res |= reverseLsb;
			n = n >> 1;
		}
		return res;
	}
};