class BrowserHistory {
public:
    vector<string> history;
    int idx=-1;
    BrowserHistory(string homepage) {
        history.resize(0);
        history.push_back(homepage);
        idx=0;
    }
    
    void visit(string url) {
        history.resize(idx+1);
        history.push_back(url);
        idx=history.size()-1;
    }
    
    string back(int steps) {
        idx-steps>=0?idx=idx-steps:idx=0;
        return history[idx];
    }
    
    string forward(int steps) {
        idx+steps>=history.size()?idx=history.size()-1:idx=idx+steps;
          return history[idx];
    }
};

/**
 * Your BrowserHistory object will be instantiated and called as such:
 * BrowserHistory* obj = new BrowserHistory(homepage);
 * obj->visit(url);
 * string param_2 = obj->back(steps);
 * string param_3 = obj->forward(steps);
 */