Added window sliding approach to find longest non repeating sub string

* added kosaraju's algorithm under /algorithms/graph

* added test case for /algorithms/graph/strongly_connected_component_kosaraju

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Co-authored-by: Rubal Singh <nbarubz@gmail.com>

* Initial commit for remove duplicates

* Made changes to readme and added test case

* Added the validate bst function

* Added the validate bst function

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Co-authored-by: Piyush Goel <piyushgoel@Piyushs-MacBook-Air-4.local>

)

* Optimize remove_duplicates from O(n²) to O(n) time complexity

Use a set for O(1) membership checks instead of checking membership in a list which is O(n). This reduces the overall time complexity from O(n²) to O(n).

Added documentation for time and space complexity.

Co-Authored-By: Keon <kwk236@gmail.com>

* Fix: Handle unhashable items in remove_duplicates

The previous optimization broke when the function received unhashable items
like lists or dicts, causing TypeError. This commit adds backward compatibility
by checking if items are hashable:
- Hashable items use set for O(1) lookup (fast path)
- Unhashable items fall back to list membership check (preserves original behavior)

This maintains the O(n) optimization for the common case while preserving
backward compatibility for all input types.

Co-Authored-By: Keon <kwk236@gmail.com>

* Fix: Apply black formatting to remove_duplicates.py

Add blank lines after imports and before function definition to comply
with black code formatting style, which is checked by CI.

Co-Authored-By: Keon <kwk236@gmail.com>

* Fix: Remove unused nonlocal/global declarations (F824 errors)

Remove unused nonlocal declarations in find_all_cliques.py and unused
global declaration in construct_tree_postorder_preorder.py to fix
flake8 F824 errors that were causing CI to fail.

These declarations were unnecessary because:
- In find_all_cliques: compsub and solutions are only mutated (append/pop),
  not reassigned, so nonlocal is not needed
- In construct_tree: pre_index is never used or assigned in this function,
  only in construct_tree_util

Also applied black formatting to both files.

Co-Authored-By: Keon <kwk236@gmail.com>

* Fix: Resolve pre-existing test failures blocking CI

Fix two pre-existing test failures that were causing CI to fail:

1. test_remove_duplicates: Added missing expected values to assertListEqual
   calls. The test was malformed with only input arrays but no expected
   outputs, causing TypeError.

2. test_summarize_ranges: Fixed summarize_ranges() to return tuples
   instead of strings. The function was converting tuples to formatted
   strings like '0-2', but tests expected tuples like (0, 2).

Both fixes align implementations with test expectations and docstrings.
Applied black formatting to both files.

Co-Authored-By: Keon <kwk236@gmail.com>

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Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: Keon <kwk236@gmail.com>