Hai friends, if any one want this criteria go thuough it .

trigger UpdateAccount on Opportunity (after insert,after delete, after update ) {
   
    if(Trigger.isInsert) {
  
    List<Account> acc=new List<Account>();
    List<Id> listIds = new List<Id>();
  
    for (opportunity childObj : Trigger.new) {
        listIds.add(childObj.AccountId);
    }
   
    Map<id,Account> mapAccounts=new Map<id,Account>([SELECT Id,TotalCount__c FROM Account where Id IN :listIds]);
         
    for (Opportunity opp :trigger.new){
        account a=mapAccounts.get(opp.AccountId);
        if(a!=null) {
            if(a.TotalCount__c == null) a.TotalCount__c =100;
            if(opp.Count__c != null) {
                a.TotalCount__c -= opp.Count__c;
                acc.add(a);
            }    
        }
        for(integer i=0;i<acc.size();i++)
        {
            update acc;
        }
    } 
    }
    
          
    if(trigger.isDelete) {
   
    List<Account> acc=new List<Account>();
    List<Id> listIds = new List<Id>();
  
        for (opportunity childObj : Trigger.old) {
            listIds.add(childObj.AccountId);
        }
        Map<id,Account> mapAccounts=new Map<id,Account>([select id, TotalCount__C from Account where id=:listIds]);
        for (opportunity childObj : Trigger.old) {
            if(childObj.AccountId != null) {       
                account ac=mapAccounts.get(childObj.AccountId);
                ac.TotalCount__c -= childObj.Count__c;
                acc.add(ac);
            }
        }
        for(integer i=0;i<acc.size();i++)
        {
              update acc;
        }
     }

   
    if(trigger.isUpdate)
    {
    List<Account> acc=new List<Account>();
    List<Id> listIds = new List<Id>();
    List<opportunity> newopp=new List<opportunity>();
   
        for (opportunity childObj : Trigger.new) {
            listIds.add(childObj.AccountId);
            newopp.add(childObj);
        }
         
        Map<id,Account> mapAccounts=new Map<id,Account>([select id, TotalCount__C from Account where id IN :listIds]);
          
        for (opportunity childObj : Trigger.New) {
            account ac=mapAccounts.get(childObj.AccountId);
            Opportunity oldOp = Trigger.oldMap.get(childObj.ID);
           
                if(ac.TotalCount__C == null) ac.TotalCount__C = 100;
               
                if(childObj.Count__c !=oldOp.count__c)
                {
                    if(oldOp.count__c>childObj.count__c)
                    {
                        Decimal i=oldOp.count__c-childObj.count__c;
                        ac.TotalCount__C =ac.TotalCount__C+i;
                        acc.add(ac);
                     }
                     else if(oldOp.count__c<childObj.count__c)
                     {
                         Decimal i=childObj.count__c-oldOp.count__c;
                         ac.TotalCount__C =ac.TotalCount__C-i;
                         acc.add(ac);
                     }
                    update acc;
               
                }
            }
        }       
}