LeetCode/190. ReverseBits

Link

• https://leetcode.com/problems/reverse-bits/

Summary

Asking that do you know bit operations.

Solutions

My Solution

Contrast to what the question was really asking, I’m not familiar with bits. So I brought arithmetic solution to solve this problem.

public uint reverseBits(uint n)
{
    uint result = 0;
    var k = 32;

    while (k >= 0)
    {
        var reminder = (n % 2);
        n /= 2;
        k--;
        if (reminder == 0) continue;
        result += (uint)Math.Pow(2, k) * reminder;
    }

    return result;
}

Best Solution

By moving bits, the problem solved. Need to get use this this.

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