Triggers 如果已创建联系人，则需要更新帐户中的自定义字段

我无法将联系人的值更新到帐户。但是代码没有错误，仍然无法更新值。请帮助我更新值

trigger CustContfield on Contact (after insert, after Update, after delete) {
    List<Account> Acclist = new List<Account>();
    List<Contact> con1list = new List<Contact>();
    Set<Id> accIds = new Set<Id>();
    if(trigger.isInsert || trigger.isUpdate) {
        for(Contact con : trigger.new){
            accIds.add(con.AccountId);
        }
         if(trigger.isDelete)
         {
            for(Contact con1 : trigger.old){
                accIds.add(con1.AccountId);
            }
        }
    }
     for(Account acc : [Select Contact_Shops__c,Id,(Select Id,YTD_Shops__c,Account.Primary_Contact__c from Contacts) from Account where Id =: accIds]) 
     {
      for(Contact con1list : Cont1){
        acc.Contact_Shops__c = Cont1.YTD_Shops__c;
        acclist.add(acc);
    }
    try
    {
        Update acclist;
    }
    catch( exception e) {
        System.debug('Exception :'+e.getMessage());
    }
}
}