Reverse bits of a given 32 bits unsigned integer.
For example, given input 43261596 (represented in binary as 00000010100101000001111010011100), return 964176192 (represented in binary as00111001011110000010100101000000).
Follow up:
If this function is called many times, how would you optimize it?
1 public class Solution { 2 // you need treat n as an unsigned value 3 public int reverseBits(int n) { 4 for(int i = 0; i < 16; i ++){ 5 int j = 31 - i; 6 if(((n >> i) & 1) != ((n >> j) & 1)){ 7 n ^= (1 << i) | (1 << j); 8 } 9 } 10 return n; 11 } 12 }
Swap two bit in the Integer:
1 public int swapBits(int val, int i, int j){ 2 if(((val >> i) & 1) != ((val >> j) & 1)){ 3 val ^= (1 << i) | (1 << j); 4 } 5 return val; 6 }
原文：http://www.cnblogs.com/reynold-lei/p/4368052.html