Reverse Bits

Reverse bits of a given 32 bits unsigned integer.

• Time: O(1)
• Space: O(1)

public int reverseBits(int n) {
    int m = 0;
    for (int i = 0; i < 32; i++, n >>= 1) {
        m <<= 1;
        m |= n & 1;
    }
    return m;
}