浙大在线评测 1078 Palindrom Numbers

Problem:

    We say that a number is a palindrom if it is the sane when read from left to right or from right to left. For example, the number 75457 is a palindrom.

    Of course, the property depends on the basis in which is number is represented. The number 17 is not a palindrom in base 10, but its representation in base 2 (10001) is a palindrom.

    The objective of this problem is to verify if a set of given numbers are palindroms in any basis from 2 to 16.

Input Format:

    Several integer numbers comprise the input. Each number 0 < n < 50000 is given in decimal basis in a separate line. The input ends with a zero.

Output Format:

Your program must print the message Number i is palindrom in basis where I is the given number, followed by the basis where the representation of the number is a palindrom. If the number is not a palindrom in any basis between 2 and 16, your program must print the message Number i is not palindrom.

Sample Input:

17
19
0

Sample Output:

Number 17 is palindrom in basis 2 4 16
Number 19 is not a palindrom


Solution:

// 声明：本代码仅供学习之用，请不要作为个人的成绩提交。
// http://blog.csdn.net/mskia
// email: [email protected]
#include <iostream>
#include <vector>
using namespace std;

int main( void ) {
    for ( ; ; ) {
        int number;
        cin >> number;
       
        if ( number == 0 ) {
            break;
        }
       
        vector< int > result;
        for ( int i = 2; i <= 16; ++i ) {
            vector< int > newnum;

            int num = number;
            while ( num != 0 ) {
                newnum.push_back( num % i );
                num /= i;
            }

            int left = 0 , right = newnum.size( ) - 1;
            for ( ; left < right; ++left , --right ) {
                if ( newnum[ left ] != newnum[ right ] ) {
                    goto NOT;
                }
            }
           
            result.push_back( i );
       
            NOT:;
        }
   
        if ( result.size( ) > 0 ) {
            cout << "Number " << number << " is palindrom in basis ";
            vector< int >::iterator p = result.begin( );
            cout << *p;
            ++p;
            for ( ; p != result.end( ); ++p ) {
                cout << " " << *p;
            }
            cout << endl;
           
        } else {
            cout << "Number " << number << " is not a palindrom" << endl;
        }
       
        result.clear( );

    }
    
    return 0;
}

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