I understand that binary tree allows only one node as its root. I am looking for data structure which allows two nodes as 1st level without root. Can we do accomplish this graph?
I have data like the following
EmpoyeeId SupervisorId DeptName
1000 -1 Business
2000 -1 Research
1001 1000 Accouns
1002 1000 Tax2
2001 2000 Computers
1003 1001 Corp Tax
2002 2001 Operating System
1008 1001 another Tax
1009 1001 big business Tax
Given above data , how do we model this? Which data structure i should use to get employee at nth level?
Having two binary trees is actually your structure.
Also you always can make virtual root node that will have no meaningful value but will point to two neighbours.
Related
I have thought long about this but couldn't figure it out. I am looking for an algorithm ( in any language) to group a bunch of people by the following these 2 rules:
Group by ascending skill level which is represented by a number (the higher the more skilled). The best and weakest in the group should not differ by more than 1 point, where possible.
Spread out people from the same country as far as possible, i.e. dont put people from the same country in the same group, while at the same time not breaking rule 1 above. A group should not consist of people from 1 country where possible.
Each group can have at most 4 person (where possible) or 3 persons e.g. if there are 18 people, then they are split into 3 groups of 4 and 2 groups of 3.
Sample data (Skill level followed by country) :
5 US
5 US
5 US
5 US
6 GB
6 GB
6 GB
7 CN
7 CN
7 CN
7 CN
7 HK
8 US
8 US
8 US
8 CA
8 CN
8 CN
..to be grouped into 2groups of 4s and 2groups of 3s
Please help if you have any idea?
thank you in advance
I would suggest the following.
First, aggregate the data by country and skill level, so the data looks more like:
US 5 4
GB 6 3
. . .
Sort this by the highest ranking first.
Then use a greedy algorithm.
Determine the number of members in the group (either size or size - 1)
Take one from the first group (highest ranking).
Continue taking one from each subsequent group meeting the country condition (so you might need to skip the US).
That defines the first group.
Then repeat.
This is not guaranteed to be optimal. But then again, optimality is not defined for the problem. Which is more important? Country diversity or skill sameness?
When comparing two objects of the same size, Javers compares 1-to-1. However, if a new change is added such as new row to one of the objects, the comparison reports changes that are NOT changes. Is it possible to have Javers ignore the addition/deletion for the sake of just comparing like objects?
Basically the indices get out of sync.
Row Name Age Phone(Cell/Work)
1 Jo 20 123
2 Sam 25 133
3 Rick 30 152
4 Rick 30 145
New List
Row Name Age Phone(Cell/Work)
1 Jo 20 123
2 Sam 25 133
3 Bill 30 170
4 Rick 30 152
5 Rick 30 145
Because Bill is added the new comparison result will say that Rows 4,5 have changed when they actually didn't.
Thanks.
I'm guessing that your 'rows' are objects representing rows in an excel table and that you have mapped them as ValueObjects and put them into some list.
Since ValueObjects don't have its own identity, it's unclear, even for a human, what was the actual change. Take a look at your row 4:
Row Name Age Phone(Cell/Work)
before:
4 Rick 30 145
after:
4 Rick 30 152
Did you changed Phone at row 4 from 145 to 152? Or maybe you inserted a new data to row 4? How can we know?
We can't. By default, JaVers chooses the simplest answer, so reports value change at index 4.
If you don't care aboute the indices, you can change the list comparision algorithm from Simple to Levenshtein distance. See https://javers.org/documentation/diff-configuration/#list-algorithms
SIMPLE algorithm generates changes for shifted elements (in case when elements are inserted or removed in the middle of a list). On the contrary, Levenshtein algorithm calculates short and clear change list even in case when elements are shifted. It doesn’t care about index changes for shifted elements.
But, I'm not sure if Levenshtein is implemented for ValueObjects, if it is not implemented yet, it's a feature request to javers-core.
I'm really new a tree sctructure and linked list, I'm a facing a theorical problem, let's say I decide to use TreeModel, seeing the sample, you basically will order the tree like:
Tree
node 1
11
12
121
122
node 2
21
211
...and so on
Considering the numbers are node's id, how would I manage them once the happen to be 2 or more digits?
node 10
101
1011
1012
102
1021
1022
10221
And so on...? using pseudo code, how do I keep the track of this? meaning, I want to get all 3er level nodels of a node? (>100 for the first 9 and >1000 for the rest???) this is actually my question itself.
I would appreciate any clarification.
TreeModel does not depend on any specific node id format, the numbers shown at the library demo page are just for illustrative purposes. Would it cause less confusion if instead of those numbers you had a string id separated by underscores?
1
1_1
1_2
...
10
10_1
10_2
Also note that TreeModel was not designed for binary trees and so it does not support in-order traversal.
I need to develop an algorithm that can locate data item position in some hierarchy. I have hierarchy that classifies elements of some dataset. Hierarchy is taxonomic - top element is the most generic class, that matches any element of the dataset, the deeper elements contain more specific classes that match some subset of the dataset.
For example, consider hierarchy of yachts. We have class Yacht at the top. In the next level we have Sailing yacht and Motor yacht. Sailing yacht has two children - Cruising yacht and Racing yacht. Cruisers can be further divided by manufacturer, for example Bavaria Yachts and Dufour Yachts. Then each of this classes can be further divided by the hull type, length, sails area and so on.
This is an example from the dataset:
Drive Class Manufacturer Hull type Len Sails Area ... Model
Sailing Cruiser Bavaria Yachts Mono-hull 25ft 560sqft ... Bavaria 32
Sailing Cruiser Dufour Yachts Mono-hull 27ft 580sqft ... Dufour 32 Classic
I can easily map each sample to hierarchy by searching it in depth-first order.
It is a simple search problem at first glance but there are some difficulties.
First difficulty: data items doesn't necessary contain all the elements. It's common that data item lacks from 10 to 50 percent of elements. Many of this elements is not very significant, for example yacht Drive can only be Motor or Sail so it doesn't bring a lot of information (only 1 bit). These elements can be inferred easily using the more significant elements, for example if we know yacht Model, we can infer all other elements(or fields) of the data-item.
Second difficulty: some elements can vary between different data items even if they correspond to the same place in the hierarchy (same yacht model). For example Sails area can vary greatly because boat owners modify they yacht's rig in a different ways or just round area value.
As I've already mentioned, I need to locate different data items from the dataset in the hierarchy. Each data item can be located with different precision. Precision is a depth in the hierarchy at which search process stops. In other words, I need to get path in the hierarchy that corresponds to each data item and this path can be incomplete. For example, algorithm can find that data items corresponds to Juliet 23 yacht but production year can still be unknown.
It would be cool if I could get multiple paths with probability measure for each. For example, algorithm can return 4 paths for Juliet 23 for different production years, each with 25% probability.
At this moment I solve this problem using depth first search with some heuristics. It gives good results but I think that it is possible to get better results. Maybe you can formulate this problem in more generic way so I can search for some academic papers about it.
I think SQL can really help you resolve your difficulties,
For your First difficulty: use NVL(field, value-if-null)
Example: Print type & production year (if it exist), of racing yachts
SELECT Y.TYPE, NVL(Y.PRDYEAR, 'UNKNOWN')
FROM T_YACHT Y WHERE Y.CLASS = 'RACING'
Example: get all Yachts which Production Year is over year 2000
SELECT * FROM T_YACHT Y WHERE
NVL(Y.PRDYEAR,TO_TIMESTAMP('01-01-0001','DD-MM-YYYY'))
> TO_TIMESTAMP('01-01-2000','DD-MM-YYYY')
For your Second difficulty: use GROUP BY\CASCADING-SQL\DISTINCT\NVL
Example: see how many types of racing yachts are there
SELECT Y.TYPE, COUNT(Y.ID) AS YACHT_TYPE
FROM T_YACHT Y
WHERE Y.CLASS = 'RACING'
GROUP BY Y.TYPE
I have high scores (name, score, time) stored in a single file and I divide them into separate arrays once it reads them, only problem is I can't figure out a way to sort all three by score and time from least to greatest and still keep the correct order of values.
For example:
Name score time
---------------
nathan 123 01:12
bob 321 55:32
frank 222 44:44
turns to:
bob 123 01:12
frank 222 44:44
nathan 321 55:32
Encapsulate the data into a single object (HighScore) that has three properties: name, time, and score. Then store them in a single array and sort the single array.
Welcome to object-oriented programming.