title: ACM-NEFUOJ-P239回文数
    tags:

    • ACM
      abbrlink: bf195a13
      date: 2020-12-20 12:58:12
    1. #include<bits/stdc++.h>
    3. using namespace std;
    5. int n,p[1000],len,p1[1000];
    6. int f()
    7. {
    8.     int i;
    9.     for(i=0;i<=len;i++)
    10.         if(p[i]!=p[len-i]) return 0;
    11.     return 1;
    12. }
    13. void f1()
    14. {
    15.     int i;
    16.     for(i=0;i<=len;i++)  p1[i]=p[len-i];
    17.     for(i=0;i<=len;i++)  p[i]+=p1[i];     
    18.     for(i=0;i<=len;i++)
    19.         p[i+1]+=p[i]/n, p[i]=p[i]%n; 
    20.     if(p[len+1]>0) len++;
    21. }
    22. int main()
    23. {
    24.     string s;
    25.     int i;
    26.     while(cin>>n>>s)
    27.     {
    28.         memset(p,0,sizeof(p));
    29.         len=s.size()-1;
    30.         for(i=len;i>=0;i--)
    31.         {
    32.             if(s[i]>='0' && s[i]<='9') p[len-i]=s[i]-'0';
    33.             if(s[i]>='A')  p[len-i]=s[i]-'A'+10;
    34.         }
    35.         if(f())  {cout<<'0'<<endl; continue;}
    36.         int t=0;
    37.         while(t<=30)
    38.         {
    39.             t++;
    40.             f1();
    41.             if(f()) { cout<<t<<endl; break; }
    42.         }
    43.         if(t>30)  cout<<"Impossible"<<endl;
    44.     }
    45.     return 0;
    46. }