palindrome (manacher)

#include <vector>
#include <iostream>
#include <string>
using namespace std;
int Manacher(string s) {
    // Insert '#'
    string t = "$#";
    for (int i = 0; i < s.size(); ++i) {
        t += s[i];
        t += "#";
    }
    // Process t
    vector<int> p(t.size(), 0);
    int mx = 0, id = 0, resLen = 0, resCenter = 0;
    for (int i = 1; i < t.size(); ++i) {
        p[i] = mx > i ? min(p[2 * id - i], mx - i) : 1;
      while (t[i + p[i]] == t[i - p[i]]) ++p[i];
        if (mx < i + p[i]) {
            mx = i + p[i];
            id = i;
        }
        if (resLen < p[i]) {
            resLen = p[i];
            resCenter = i;
        }
    }
    return resLen - 1;
}
int main() {
    string s1;
    int k=0;
  while(1)
 {
        k++;
     cin>>s1;
       if(s1[0]=='E')
       break;
       else
     {
            cout<<"Case "<<k<<": "<<Manacher(s1)<<endl;
        }
     } 
   return 0;
}