Topcoder 701, 1, div2

topcoder_701_1.cpp

#include <bits/stdc++.h>
using namespace std;

class  SquareFreeString {
public:
    string isSquareFree(string s) {
        if (s.length() < 2)
            return "square-free";
        for (int l = 2; l <= s.length(); l += 2) {
            for (int shift = 0; shift < s.length() - l + 1; ++shift) {
                bool res = true;
                for (int i = 0; i < l/2; ++i) {
                    res = res && (s[shift + i] == s[shift + i+l/2]);
                    //cout << l << shift << i <<"| " <<shift + i << " " << shift + 2*i+l/2 << "| "  << s[shift + i] << " " << s[shift + i+l/2] << "AA\n";
                }
                if (res)
                    return "not square-free";
            }
        }
        return  "square-free";
    }
};

int main(int, char**) {
    SquareFreeString sq;
    string s;
    cin >> s;
    cout << sq.isSquareFree(s);

    return 0;
}