Map<Schema.SObjectType,List<Id>> InputObjectsByType = new Map<Schema.SObjectType,List<Id>>();
For(Id i:InputIds){
  Schema.SObjectType t = i.getSObjectType();
  If(InputObjectsByType.containsKey(t){
    InputObjectsByType.get(t).add(i);
  } else {
    InputObjectsByType.put(t, new List<Id>{i});
  }
}
