Generic implementation of optimal grouping of objects using dynamic programming

[pravalikavis]

References to other Issues or PRs or Relevant literature

fixes #230

Brief description of what is fixed or changed

1. Added a file which has an optimal_grouping method which groups the given objects based on the cost input function.
2. This function uses dynamic programing which reduces the time complexity
3. It can be used on problems like Matrix chain multiplication, optimal binary search tree and on any other problem that follows the two rules of dynamic programming along with divide and conquer.

Other comments

[czgdp1807]

The algorithm will work on an array of objects if I am not wrong. So, the code should be shifted to pydatastructs/pydatastructs/linear_data_structures/algorithms.py.

[pravalikavis]

I have moved the file to linear_data_structures.

[czgdp1807]

Hi, The code is having too many checks. Can you please simplify it? And the code should be appended to https://github.com/codezonediitj/pydatastructs/blob/master/pydatastructs/linear_data_structures/algorithms.py

[pravalikavis]

Hi, I moved the code to the specified file and removed some type checks.

[czgdp1807]

Add some tests for your patch. See tests folder under linear_data_structures. The build is failing. Make it work.

[codecov[bot]]

Codecov Report

Merging #272 into master will decrease coverage by 0.180%. The diff coverage is 89.583%.

@@              Coverage Diff              @@
##            master      #272       +/-   ##
=============================================
- Coverage   98.842%   98.662%   -0.181%     
=============================================
  Files           23        23               
  Lines         2420      2467       +47     
=============================================
+ Hits          2392      2434       +42     
- Misses          28        33        +5     

Impacted Files	Coverage Δ
pydatastructs/linear_data_structures/__init__.py	100.000% <ø> (ø)
pydatastructs/linear_data_structures/algorithms.py	96.815% <89.583%> (-3.185%)	:arrow_down:

[pravalikavis]

Hi, I have made the changes.

[Smit-create]

@pravalikavis Please resolve merge conflicts.

[czgdp1807]

My only concern with dynamic programming problems is that they aren't that abstract and generalized. Moreover, they are pseudo-polynomial solutions to optimisation problems (mostly discrete). So possibly, we can add a separate optimisation module and put the dynamic programming solutions there. In fact they can also contain parametrised approximation algorithm. Anyways, we should first check if there is already a python package for solving these kind of formulations.

[Smit-create]

Agreed on this