[leetcode] Reverse Bits

Reverse Bits

Reverse bits of a given 32 bits unsigned integer.

For example, given input 43261596 (represented in binary as 00000010100101000001111010011100), return 964176192 (represented in binary as 00111001011110000010100101000000).

Follow up:
If this function is called many times, how would you optimize it?

Related problem: Reverse Integer

Credits:
Special thanks to @ts for adding this problem and creating all test cases.

 

class Solution
{
public:
  uint32_t reverseBits(uint32_t n)
  {
    int A[32] = {0};
    int i = 0;
    while(n > 0)
    {
      A[i++] = n % 2;
      n /= 2;
    }

    int sum = 0;
    for(i = 0; i < 32; i++)
      sum = sum * 2 + A[i]; 

    return sum;
  }
};