给定一个整数“x”，编写一个C函数，如果x的二进制表示形式是回文形式，则返回true，否则返回false。 例如，二进制表示为10的数字。。01是回文数字，二进制表示为10。。00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，逐个比较位。如果发现不匹配，则返回false。
null
算法： isPalindrome（x） 1） 使用sizeof（）运算符查找x中的位数。 2） 将左侧和右侧位置分别初始化为1和n。 3） 当左侧的“l”小于右侧的“r”时，执行以下操作。 ..…..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do l++和r–。 4） 如果我们到了这里，这意味着我们没有发现任何不匹配的地方。 为了在给定位置找到位，我们可以使用类似于 这 邮递表达方式“ x和（1< “如果设置了从右侧开始的第k位，则给出非零值；如果未设置第k位，则给出零值。”。
下面是上述算法的实现。
C++
// C++ Program to Check if binary representation // of a number is palindrome #include<iostream> 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 |
PHP
<?php // PHP 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 ) { return ( $x & (1 << ( $k - 1))) ? true : false; } // This function returns true if binary // representation of x is palindrome. // For example (1000...001) is palindrome function isPalindrome( $x ) { $l = 1; // Initialize left position $r = sizeof(4) * 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 $x = 1 << 15 + 1 << 16; echo isPalindrome( $x ), "" ; $x = 1 << 31 + 1; echo isPalindrome( $x ), "" ; // This code is contributed by ajit. ?> |
Javascript
<script> // 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 </script> |
输出：
11
时间复杂度：O（x）
辅助空间：O（1）
本文由 苏拉布·古普塔 。如果您发现任何不正确的地方，或者您想分享有关上述主题的更多信息，请发表评论。
© 版权声明
文章版权归作者所有，未经允许请勿转载。
THE END
![关于”PostgreSQL错误：关系[表]不存在“问题的原因和解决方案-yiteyi-C++库](https://www.yiteyi.com/wp-content/themes/zibll/img/thumbnail.svg)
