feat(Python): add Segment Tree (range sum) implementation + tests

[Pasan11504]

Add Segment Tree (range sum) implementation in Python

Summary

This PR adds a Segment Tree implementation for range sum queries and point updates under:
Python/data_structures/segment_tree.py.

Files added

• Python/data_structures/segment_tree.py — SegmentTree class (range sum, point update)
• Python/data_structures/README.md — short usage guide
• Python/data_structures/test_segment_tree.py — pytest unit tests

Why this is useful

• Segment Trees are a common range-query data structure useful for competitive programming and algorithm learning.
• This fills a gap in Python/data_structures/ and provides a tested, documented reference implementation.

Test & Usage

• Tests included (requires pytest)
• Example:

from segment_tree import SegmentTree
arr = [1,3,5,7,9,11]
st = SegmentTree(arr)
print(st.range_sum(1,3))  # 15
st.update(1, 10)
print(st.range_sum(1,3))  # 22

[github-actions]

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[github-actions]

🤖 Automated PR Status

🔍 Code Validation

✅ Passed - File naming and structure look good!

🧪 Compilation Tests

✅ Passed - All code compiles successfully!

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[admirerr]

Approved