C++ libraries

#include <bits/stdc++.h>
#include <cstring>
#include <string>
#include <string.h>
#include <math.h>
#include <stdio.h>
#include <ctime>
#include <cmath>
#include <algorithm>
#include <tuple>
#include <functional>
#include <utility>
#include <cstdio>
#include <deque>
#include <vector>
using namespace std;
vector <int> roads[2001];

string operator*(string s, size_t count)
{
    string ret="";
    for(size_t i = 0; i < count; ++i)
    {
        ret = ret + s;
    }
    return ret;
}

int main()
{
    int M,longestlen,repeats;
    scanf("%d",&M);
    string s;
    double ans;
    for (int i=0;i<M;i++)
    {
        int len=0;
        scanf("%d %s",&len,&s);
        printf("%s\n",s.substr(0,2));
        printf("%s %s\n",s.substr(0,2) ,s.substr(s.length()-2+1  ,s.length()-2) );
        for (int j=2;j<=(int)ceil((double)M/2)+1;j++)
        {
            string x=s.substr(0,j);
            string y=s.substr(s.length()-j+1,s.length()-j);
            if ( x==y  && M%j==0)
            {
                len=j;
            }
        }
        if (len>longestlen)
        {
            longestlen=len;
            repeats=M/longestlen;
        }
    }
    printf("%d%d\n",longestlen,repeats);
    ans=longestlen/(double)repeats;
    printf("%f",ans);
    return 0;
}