给定一个无符号整数，将所有奇数位与偶数位交换。例如，如果给定的数字为23( 0 0 0 1 0 1 1 1)，则应将其转换为43(0 0 1 0 1 0 1 1 )。每个偶数位置位都与右侧的相邻位交换(偶数位置位以23的二进制表示形式突出显示)，每个奇数位置位均与左侧的相邻位交换。
如果我们仔细查看该示例，可以观察到，我们基本上需要将所有偶数位(>>在上面的示例中，23的偶数位都突出显示)右移(>>)，以使它们变为奇数位(突出显示)在43中)，然后将所有奇数位左移(<<)1，以使它们变为偶数位。基于此观察结果，以下解决方案。该解决方案假定输入数字使用32位存储。
设输入数字为x
1)通过按位执行x的所有偶数位，并用0xAAAAAAAA执行x的所有偶数位。数字0xAAAAAAAA是32位数字，所有偶数位均设置为1，所有奇数位均设置为0。
2)通过按位执行x的所有奇数位，并使用0x55555555获得x的所有奇数位。数字0x55555555是32位数字，所有奇数位均设置为1，所有偶数位均设置为0。
3)右移所有偶数位。
4)将所有奇数位左移。
5)合并新的偶数和奇数位并返回。
C++
// C++ program to swap even and
// odd bits of a given number
#include
using namespace std;
// Function to swap even
// and odd bits
unsigned int swapBits(unsigned int x)
{
// Get all even bits of x
unsigned int even_bits = x & 0xAAAAAAAA;
// Get all odd bits of x
unsigned int odd_bits = x & 0x55555555;
even_bits >>= 1; // Right shift even bits
odd_bits <<= 1; // Left shift odd bits
return (even_bits | odd_bits); // Combine even and odd bits
}
// Driver code
int main()
{
unsigned int x = 23; // 00010111
// Output is 43 (00101011)
cout< C
// C program to swap even and
// odd bits of a given number
#include
// Function to swap even
// and odd bits
unsigned int swapBits(unsigned int x)
{
// Get all even bits of x
unsigned int even_bits = x & 0xAAAAAAAA;
// Get all odd bits of x
unsigned int odd_bits = x & 0x55555555;
even_bits >>= 1; // Right shift even bits
odd_bits <<= 1; // Left shift odd bits
return (even_bits | odd_bits); // Combine even and odd bits
}
// Driver program to test above function
int main()
{
unsigned int x = 23; // 00010111
// Output is 43 (00101011)
printf("%u ", swapBits(x));
return 0;
} Java
// Java program to swap even
// and odd bits of a given number
class GFG{
// Function to swap even
// and odd bits
static int swapBits(int x)
{
// Get all even bits of x
int even_bits = x & 0xAAAAAAAA;
// Get all odd bits of x
int odd_bits = x & 0x55555555;
// Right shift even bits
even_bits >>= 1;
// Left shift even bits
odd_bits <<= 1;
// Combine even and odd bits
return (even_bits | odd_bits);
}
// Driver program to test above function
public static void main(String[] args)
{
int x = 23; // 00010111
// Output is 43 (00101011)
System.out.println(swapBits(x));
}
}
// This code is contributed by Smitha Dinesh SemwalPython 3
# Python 3 program to swap even
# and odd bits of a given number
# Function for swapping even
# and odd bits
def swapBits(x) :
# Get all even bits of x
even_bits = x & 0xAAAAAAAA
# Get all odd bits of x
odd_bits = x & 0x55555555
# Right shift even bits
even_bits >>= 1
# Left shift odd bits
odd_bits <<= 1
# Combine even and odd bits
return (even_bits | odd_bits)
# Driver program
# 00010111
x = 23
# Output is 43 (00101011)
print(swapBits(x))
# This code is contributed
# by Nikita Tiwari.C#
// C# program to swap even and odd bits
// of a given number
using System;
class GFG {
// Function to swap even
// and odd bits
static long swapBits(int x)
{
// Get all even bits of x
long even_bits = x & 0xAAAAAAAA;
// Get all odd bits of x
long odd_bits = x & 0x55555555;
// Right shift even bits
even_bits >>= 1;
// Left shift even bits
odd_bits <<= 1;
// Combine even and odd bits
return (even_bits | odd_bits);
}
// Driver program to test above function
public static void Main()
{
int x = 23; // 00010111
// Output is 43 (00101011)
Console.Write(swapBits(x));
}
}
// This code is contributed by Sam007.PHP
>= 1;
// Left shift odd bits
$odd_bits <<= 1;
// Combine even and odd bits
return ($even_bits | $odd_bits);
}
// Driver Code
// 00010111
$x = 23;
// Output is 43 (00101011)
echo swapBits($x);
// This code is contributed by Ajit
?>Javascript
输出：
43