Leetcode 190. Reverse Bits

Reverse Bits

• Total Accepted: 71291
• Total Submissions: 242226
• Difficulty: Easy

Reverse bits of a given the unsigned integer.

For example, given input 43261596 (represented in binary as 00000010100101000001111010011100), return 964176192 ( Represented in binary as 00111001011110000010100101000000).

followup: What would you optimize it when this function is called many times?

Idea: Binary number reversal.

Code:

Method One:

1 classSolution {2  Public:3 uint32_t reversebits (uint32_t N) {4n = (n >> -) | (N << -);5n = ((N &0xff00ff00) >>8) | (N &0x00ff00ff) <<8);6n = ((N &0xf0f0f0f0) >>4) | (N &0x0f0f0f0f) <<4);7n = ((N &0XCCCCCCCC) >>2) | (N &0x33333333) <<2);8n = ((N &0xaaaaaaaa) >>1) | (N &0x55555555) <<1);9         returnN;Ten     } One};

Method Two:

1 classSolution {2  Public:3 uint32_t reversebits (uint32_t N) {4         inti;5uint32_t res=0;6          for(i=0;i< +; i++){7res<<=1;8res|=n&1;9n>>=1;Ten         } One         returnRes; A     } -};

Leetcode 190. Reverse Bits