Implement dsu size of the group

[sak-codes]

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[codecov[bot]]

Codecov Report

Merging #516 (394c9ee) into master (8f419fd) will increase coverage by 0.001%. The diff coverage is 100.000%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #516 +/- ## ============================================= + Coverage 98.528% 98.530% +0.001% ============================================= Files 32 32 Lines 4010 4014 +4 ============================================= + Hits 3951 3955 +4 Misses 59 59 ``` | [Impacted Files](https://codecov.io/gh/codezonediitj/pydatastructs/pull/516?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=codezonediitj) | Coverage Δ | | |---|---|---| | [...ucts/miscellaneous\_data\_structures/disjoint\_set.py](https://codecov.io/gh/codezonediitj/pydatastructs/pull/516?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=codezonediitj#diff-cHlkYXRhc3RydWN0cy9taXNjZWxsYW5lb3VzX2RhdGFfc3RydWN0dXJlcy9kaXNqb2ludF9zZXQucHk=) | `100.000% <100.000%> (ø)` | | [](https://codecov.io/gh/codezonediitj/pydatastructs/pull/516?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=codezonediitj)