Overview

Given a 32-bit unsigned integer n, reverse its bits and return the result as an unsigned integer.

For example, the 32-bit representation of 43261596 is 00000010100101000001111010011100. Reversing gives 00111001011110000010100101000000, which is 964176192.

Constraints

• Input is a 32-bit unsigned integer (0 <= n <= 2^32 - 1).
• Return a 32-bit unsigned integer.
• Use bitwise operations for an efficient solution.

Examples

reverseBits(43261596);
// => 964176192
// Binary: 00000010100101000001111010011100
// Reversed: 00111001011110000010100101000000

reverseBits(0);
// => 0

reverseBits(1);
// => 2147483648  (1 followed by 31 zeros)

Solution

function reverseBits(n) {
  let result = 0;
  for (let i = 0; i < 32; i++) {
    result = (result * 2) + (n & 1);
    n = Math.floor(n / 2);
  }
  return result;
}

Resources

• Reverse Bits — LeetCode
• Bitwise Operations — MDN