while i am uploading from csv file i need to create account and contact i have achieved this using apex code. i need to check whether the account name already exist or not. Whether i need to write apex trigger for this. kindly give me any idea to solve this. i am not using Dataloader i need to do this using programming.

code:

```
 public Pagereference ReadFile()
 {
    nameFile=contentFile.toString();
    filelines = nameFile.split('\n');
    accstoupload = new List<Account>();
    contoupload = new List<Contact>();
    opptoupload = new List<Opportunity>();
    custtoupload = new List<CustomLead__c>();
            for (Integer i=1;i<filelines.size();i++)
    {
        String[] inputvalues = new String[]{};
        inputvalues = filelines[i].split(',');

        Account a = new Account();
        a.Name = inputvalues[0];

        accstoupload.add(a);
    }
    try
    {
    insert accstoupload;
    }
    catch (Exception e) {
        ApexPages.Message errormsg = new ApexPages.Message(ApexPages.severity.ERROR,'An error has occured. Please check the template or try again later');
        ApexPages.addMessage(errormsg);
    }    

```