检查数字的二进制表示形式是否是回文

给定一个整数“ x”，编写一个C函数，如果x的二进制表示是回文，则返回true，否则返回false。
例如，二进制表示为10..01的数字是回文，二进制表示为10..00的数字不是回文。
这个想法类似于检查字符串是否为回文。我们从最左边和最右边的位开始，并逐位比较位。如果发现不匹配，则返回false。

算法：
isPalindrome(x)
1)使用sizeof()运算符查找x中的位数。
2)分别将左位置和右位置初始化为1和n。
3)在左“ l”小于右“ r”时进行跟随。
..…..a)如果位置“ l”处的位与位置“ r”处的位不同，则返回false。
..…..b)递增“ l”和递减“ r”，即，执行l ++和r–。
4)如果我们到达这里，则意味着我们没有找到不匹配的位。
为了找到给定位置的钻头，我们可以使用类似于本文的想法。如果设置了从右起第k个位置的位，则表达式“ x＆(1 <<(k-1)) ”给出非零值；如果未设置第k个位，则表达式为零。

以下是上述算法的实现。

C++

// C++ Program to Check if binary representation
// of a number is palindrome
#include
using namespace std;
 
// This function returns true if k'th bit in x
// is set (or 1). For example if x (0010) is 2
// and k is 2, then it returns true
bool isKthBitSet(unsigned int x, unsigned int k)
{
    return (x & (1 << (k - 1))) ? true : false;
}
 
// This function returns true if binary
// representation of x is palindrome.
// For example (1000...001) is palindrome
bool isPalindrome(unsigned int x)
{
    int l = 1; // Initialize left position
    int r = sizeof(unsigned int) * 8; // initialize right position
 
    // One by one compare bits
    while (l < r)
    {
        if (isKthBitSet(x, l) != isKthBitSet(x, r))
            return false;
        l++; r--;
    }
    return true;
}
 
// Driver Code
int main()
{
    unsigned int x = 1 << 15 + 1 << 16;
    cout << isPalindrome(x) << endl;
    x = 1 << 31 + 1;
    cout << isPalindrome(x) << endl;
    return 0;
}

Java

// Java Program to Check if binary representation
// of a number is palindrome
class GFG
{
 
    // This function returns true if k'th bit in x
    // is set (or 1). For example if x (0010) is 2
    // and k is 2, then it returns true
    static int isKthBitSet(long x, long k)
    {
        int rslt = ((x & (1 << (k - 1))) != 0) ? 1 : 0;
        return rslt;
    }
     
    // This function returns true if binary
    // representation of x is palindrome.
    // For example (1000...001) is palindrome
    static int isPalindrome( long x)
    {
        long l = 1; // Initialize left position
        long r = (Integer.SIZE/8 )* 8; // initialize right position
     
        // One by one compare bits
        while (l < r)
        {
            if (isKthBitSet(x, l) != isKthBitSet(x, r))
            {
                return 0;
            }
            l++; r--;
        }
        return 1;
    }
     
    // Driver Code
    public static void main (String[] args)
    {
        long x = 1 << 15 + 1 << 16 ;
        System.out.println(isPalindrome(x));
         
        x = (1 << 31) + 1 ;
        System.out.println(isPalindrome(x));
    }
}
 
// This code is contributed by AnkitRai01

Python3

# python 3 Program to Check if binary representation
# of a number is palindrome
import sys
# This function returns true if k'th bit in x
# is set (or 1). For example if x (0010) is 2
# and k is 2, then it returns true
def isKthBitSet(x, k):
    if ((x & (1 << (k - 1))) !=0):
        return True
    else:
        return False
 
# This function returns true if binary
# representation of x is palindrome.
# For example (1000...001) is palindrome
def isPalindrome(x):
    l = 1 # Initialize left position
    r = 2 * 8 # initialize right position
 
    # One by one compare bits
    while (l < r):
        if (isKthBitSet(x, l) != isKthBitSet(x, r)):
            return False
        l += 1
        r -= 1
     
    return True
 
# Driver Code
if __name__ =='__main__':
    x = 1 << 15 + 1 << 16
    print(int(isPalindrome(x)))
    x = 1 << 31 + 1
    print(int(isPalindrome(x)))
 
# This code is contributed by
# Surendra_Gangwar

C#

// C# Program to Check if binary representation
// of a number is palindrome
using System;
 
class GFG
{
 
    // This function returns true if k'th bit in x
    // is set (or 1). For example if x (0010) is 2
    // and k is 2, then it returns true
    static int isKthBitSet(long x, long k)
    {
        int rslt = ((x & (1 << (int)(k - 1))) != 0) ? 1 : 0;
        return rslt;
    }
     
    // This function returns true if binary
    // representation of x is palindrome.
    // For example (1000...001) is palindrome
    static int isPalindrome( long x)
    {
        long l = 1; // Initialize left position
        long r = 4 * 8; // initialize right position
     
        // One by one compare bits
        while (l < r)
        {
            if (isKthBitSet(x, l) != isKthBitSet(x, r))
            {
                return 0;
            }
            l++; r--;
        }
        return 1;
    }
     
    // Driver Code
    public static void Main ()
    {
        long x = 1 << 15 + 1 << 16 ;
        Console.WriteLine(isPalindrome(x));
         
        x = (1 << 31) + 1 ;
        Console.WriteLine(isPalindrome(x));
    }
}
 
// This code is contributed by AnkitRai01

Javascript

 
// Javascript program to Check if binary
// representation of a number is palindrome
 
// This function returns true if k'th bit in x
// is set (or 1). For example if x (0010) is 2
// and k is 2, then it returns true
function isKthBitSet(x, k)
{
    let rslt = ((x & (1 << (k - 1))) != 0) ? 1 : 0;
    return rslt;
}
   
// This function returns true if binary
// representation of x is palindrome.
// For example (1000...001) is palindrome
function isPalindrome(x)
{
     
    // Initialize left position
    let l = 1;
     
    // initialize right position
    let r = 4 * 8;
   
    // One by one compare bits
    while (l < r)
    {
        if (isKthBitSet(x, l) !=
            isKthBitSet(x, r))
        {
            return 0;
        }
        l++; r--;
    }
    return 1;
}
 
// Driver code
let x = 1 << 15 + 1 << 16;
document.write(isPalindrome(x) + "</br>");
 
x = (1 << 31) + 1;
document.write(isPalindrome(x));
 
// This code is contributed by divyesh072019
 

输出：

1
1