題目：

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

思路：

  • 題意：給定一個無符號數，把他的二進位制位轉換過來
  • 考慮首先把原數字右移，然後得到右移的數字，賦值給新數字，然後左移動

    • -

程式碼：

public class Solution {
    // you need treat n as an unsigned value
    public int reverseBits(int n) {
         int res = 0;
        for(int i = 0; i < 32; i++, n >>= 1){
            res = res << 1 | (n & 1);
        }
        return res;
    }
}