ZOJ Problem Set - 1078 Palindrom Numbers

ZOJ Problem Set - 1078

Palindrom Numbers

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Time Limit: 2 Seconds                                     Memory Limit: 65536 KB                            

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Statement of the 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

AC代码：

#include<iostream>
#include<stdio.h>
#include<string>
using namespace std;
int a[1000];
bool isp(int len)
{
 int k=(len)/2;
 for(int i=0;i<k;i++)
 {
  if(a[0+i]!=a[len-1-i])
    return false;
 }
 return true;
}
int main()
{
 int num;
 while((cin>>num)&&num)
 {
  string re="";
  for(int i=2;i<=16;i++)
  {
   int temp=num;
   int len=0;
   while(temp)
   {
    a[len++]=temp%i;
    temp/=i;
   }
   if(isp(len))
   {
   re+=i; 
   }
  }
  if(re!="")
   {
    cout<<"Number "<<num<<" is palindrom in basis";
    for(int i=0;i<re.length();i++)
    {
     cout<<" "<<(int)re[i];
    }
    cout<<endl;
   }
   else
   {
    cout<<"Number "<<num<<" is not a palindrom"<<endl;
   }
 }
}