Create a map instead of list and finally insert or update the map values.
Sample Code:
Map<Id, Account> mapAccount = new Map<Id, Account>();
for(Account acc : listAccount){
...............
...............
mapAccount.put(acc.Id, acc);
}
update mapAccount.values();
Sample Code:
Map<Id, Account> mapAccount = new Map<Id, Account>();
for(Account acc : listAccount){
...............
...............
mapAccount.put(acc.Id, acc);
}
update mapAccount.values();