Leetcode 190 Reverse Bits

標籤：

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?

轉換成2進位的string後反轉，並且末尾補上原數不足32位的0的個數（乘以2的x次方）。

def reverse_bits(n)    2**(32-n.to_s(2).length)*n.to_s(2).reverse.to_i(2)end

 這個方法每次左移一位，末尾增加原來的末位元，迴圈32次後得到翻轉數。

uint32_t reverseBits(uint32_t n) {    uint32_t m = 0;    for (int i = 0; i< 32 ; i++,n/=2)        m = (m<<1) + (n%2);    return m;}

 

Leetcode 190 Reverse Bits