【LeetCode】190. Reverse Bits

问题描述

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?

分析

先将数字换成二进制形式，然后逆序再将二进制换成十进制即可

代码

class Solution {
public:
    uint32_t reverseBits(uint32_t n) {
    	int arr[32]={0};
		int i=0;
		while(n) {
			arr[i++] = n%2;
			n/=2;
		}
		uint32_t r = 0;
		for(i=0;i<32;i++) {
			r = r*2 + arr[i];
		} 
        return r;
    }
};