blob: d6bd60c1e898e1ddf41ff89c0b1d4cdc9837faf4 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
|
// 190. Reverse Bits
#include "leetcode.h"
#include <stdio.h>
/*
* reverse the bitof a given 32 bits unsigned integer.
*/
uint32_t reverseBits(uint32_t n) {
n = ((n & 0xFFFF0000) >> 16) | ((n & 0x0000FFFF) << 16);
n = ((n & 0xFF00FF00) >> 8) | ((n & 0x00FF00FF) << 8);
n = ((n & 0xF0F0F0F0) >> 4) | ((n & 0x0F0F0F0F) << 4);
n = ((n & 0xCCCCCCCC) >> 2) | ((n & 0x33333333) << 2);
n = ((n & 0xAAAAAAAA) >> 1) | ((n & 0x55555555) << 1);
return n;
}
int main() {
uint32_t n1 = 0b00000010100101000001111010011100;
uint32_t n2 = 0b11111111111111111111111111111101;
uint32_t r1 = reverseBits(n1);
uint32_t r2 = reverseBits(n2);
printf("%d (", r1); // expect: 964176192 (00111001011110000010100101000000)
while (r1) {
printf("%d", r1 & 1 ? 1 : 0);
r1 >>= 1;
}
printf(")\n");
printf("%d (", r2); // expect: 3221225471 (10111111111111111111111111111111)
while (r2) {
printf("%d", r2 & 1 ? 1 : 0);
r2 >>= 1;
}
printf(")\n");
}
|