Compression Algo Unfinished

#include <bits/stdc++.h>

using namespace std;

string COMPRESS(string s, int increment) {
    string unchanged = s;
    s += 'O';

    /*if ((s.size() - 2) / increment == 2) {
        if (s.substr(0, increment) == s.substr(increment, increment)) {
            return s.substr(0, increment) + 'R';
        }

        return s;
    }*/

    if (s.size() == 1) return "";

    string out = "";
    int last_i = 0;
    for (int i = increment; i <= s.size() - increment - 1; i += increment) {

        /*cout << s.substr(i - increment, increment) << " " << s.substr(i, increment) << endl;
        cout << " increment: " << increment << endl;
        cout << " s.size() = " << s.size() << endl;
        cout << " i, increment: " << (i + increment >= s.size()) << endl;*/

        if (s.substr(i - increment, increment) == s.substr(i, increment)) {
            out = out + s.substr(i - increment, increment) + 'R';
            i += increment;
        } else {
            out += s.substr(i - increment, increment);
        }

        last_i = i;
    }

    // cout << last_i << endl;

    string ELSE = s.substr(last_i, s.size() - (last_i) - 2);
    out += ELSE;

    // cout << " ELSE: " << ELSE << endl;
    // cout << " OUT: " << out << endl;

    return out;
}

int main()
{
    string s;
    cin >> s;

    string compressed = s;
    string toMatch = s;
    // this compresses the string as much as it can
    for (int k = 0; true; ++k) {
        bool notFailed = false;
        // this loop goes through every possible length match
        // ex:  abababbabb => if i = 2:
        //      ab ab ab ba ab b
        // out: abRabbaabb => i++
        for (int i = 1; i < ceil(s.size() / 2.00); ++i) {
            compressed = COMPRESS(compressed + 'S', i);
            if (!compressed.compare(toMatch)) {
                toMatch = compressed;
                notFailed = true;
            }
        }

        if (!notFailed) break;
    }

    cout << compressed.size() << endl;

    // cout << "FINAL : " << COMPRESS(s + "S", 1) << endl;

    return 0;
}