Previous/Next Permutation

[czgdp1807]

Description of the problem

We should add previous and next permutation algorithm to pydatastructs. A good place to add it will be miscellaneous_data_structures.algorithm.

Example of the problem

Following is the interface of the above algorithm in my mind,

previous_perm(sequence) -> Output will be a sequence
next_perm(sequence) -> Output will be a sequence

next_perm([1, 2, 3]) -> [1, 3, 2]

References/Other comments

[1] http://www.cplusplus.com/reference/algorithm/next_permutation/
[2] http://www.cplusplus.com/reference/algorithm/next_permutation/

[pratikgl]

I want to work on this.