/*
  NAME : Nursoltan
  PROB : calfflac
  LANG : C++
  DATE : 24/06/11 19:25
*/
#include <algorithm>
#include <bitset>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <sstream>
#include <iostream>
#include <map>
#include <set>
#include <stack>
#include <utility>
#include <queue>

using namespace std;

#define MAX 100
#define INF INT_MAX
#define eps (1e-9)

#define FOR(_i,_k,_n) for(int (_i)=(_k); (_i)<(_n); (_i)++)
#define FORR(_i,_k,_n) for(int (_i)=(_k); (_i)>=(_n); (_i)--)
#define CLR(_x) memset((_x),0,sizeof(_x))
#define SQR(_x) ((_x)*(_x))
#define all(_x) _x.begin(),_x.end()
#define sz(_x) sizeof(_x)

#define vc vector<int>
#define pb push_back
#define mp make_pair
#define iss istringstream
#define oss ostringstream
#define px first
#define py second

typedef long long ll;
typedef pair <int,int> point;
int ABS(int _x){ return _x>0?_x:-_x; }

bool isLetter(char ch){
     return ((ch>='A' && ch<='Z') || (ch>='a' && ch<='z'));
}

char lower(char ch){
     return (isupper(ch))?(ch-'A'+'a'):ch;
}

char t[20005];
int m;

int go(int i, int j){
    int ret=0;
    while(i>=0 && j<m && t[i]==t[j]) ret++,i--,j++;
    return ret;
}

int main(){
    freopen("calfflac.in","r",stdin);
    freopen("calfflac.out","w",stdout);
    
    int len,ret,b,e,n=0;
    char s[20005];
    int id[20005];
    
    CLR(s); CLR(id); CLR(t);
    FOR(i,0,20005) id[i]=-1;
    
    char ch; 
    while((ch=getchar())!=EOF) s[n++]=ch;
    
    m=0;
    FOR(i,0,n) 
      if(isLetter(s[i])){  
        id[i]=m;
        t[m++]=lower(s[i]);
      }
    
    //FOR(i,0,m) cout<<t[i];
    //cout<<endl;
      
    len=1; b=0; e=0;
    FOR(i,0,m-1){
      int k,_len;
      k=go(i,i)-1;
      _len=2*k+1;
      if(_len>len){ len=_len; b=i-k; e=i+k+1; }
      
      k=go(i,i+1);
      _len=2*k;
      if(_len>len){ len=_len; b=i-k+1; e=i+k+1; }
      
      //cout<<go(i,i)<<" "<<go(i,i+1)<<endl;
    }
    
    cout<<len<<endl;
    int i=0;
    while(id[i]==-1 || id[i]<b) i++;
    while(i<n && id[i]==-1 || (id[i]>=b && id[i]<e)){
      cout<<s[i];
      if(id[i]==e-1) break;
      i++;
    }
    cout<<endl;
    
    //system("pause");
    return 0;
}

Ch1 : Calf Flac

C++