Function dfs

String Algorithms/Repeating Substring.cpp:64–73

}

void dfs(int u = 0){
    vis[u] = true;
    if(node[u].len > bestlen && node[u].cnt > 1 && u != 0){
        bestidx = node[u].firstpos - node[u].len + 1;
        bestlen = node[u].len;
    }
    for(const auto& [c, v] : node[u].nxt)
        if(!vis[v])
            dfs(v);
}

int main(){
    scanf(" %s", S);