Trigger on contact to create account with the last name of contact and update contact with related account

trigger ContactAccountCreate on Contact (before insert,before update){
    List<String> conlst = new List<String>();
    map<string,id> mp = new map<string,id>();
    for(Contact con : Trigger.new){
        conlst.add(con.lastname);
    }
    List<Account> aclst = new List<Account>();
    for(String lm : conlst){
        Account ac = new Account();
        ac.Name = lm;
        aclst.add(ac);
    }
    if(aclst.size()>0){
        insert aclst;
    }
    for(Account a : aclst){
       mp.put(a.name,a.id); 
    }
    for(Contact con : Trigger.new){
       con.AccountId = mp.get(con.lastname);
    }
}