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Fix binary search to return first occurrence for duplicates#14452

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Pranavwagh1 wants to merge 3 commits intoTheAlgorithms:masterfrom
Pranavwagh1:master
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Fix binary search to return first occurrence for duplicates#14452
Pranavwagh1 wants to merge 3 commits intoTheAlgorithms:masterfrom
Pranavwagh1:master

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@Pranavwagh1 Pranavwagh1 commented Mar 26, 2026

Describe your change:

  • Add an algorithm?
  • Fix a bug or typo in an existing algorithm?
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@Pranavwagh1
Fix binary search to return first occurrence for duplicates
4b7c11c 
### Fix: Binary Search Incorrect Output for Duplicates

Previously, the binary_search function returned any matching index when duplicates were present.

This change modifies the implementation to return the **first occurrence** of the target element.

### Changes made:
- Introduced a `result` variable to track the first occurrence
- Continued searching in the left half after finding a match
- Updated final return to return `result` instead of immediate index

### Example:
Input: [1, 2, 2, 2, 3], target = 2  
Output (before): could be 1, 2, or 3  
Output (after): 1 (first occurrence)

This resolves issue: TheAlgorithms#13840
@Pranavwagh1
Merge branch 'master' into master
cad2dac
@Pranavwagh1
Clean up spacing in binary_search.py
238680d 
Removed unnecessary spaces before and after the return statement and the result assignment.
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algorithms-keeper bot commented Mar 26, 2026

Closing this pull request as invalid

@Pranavwagh1, this pull request is being closed as none of the checkboxes have been marked. It is important that you go through the checklist and mark the ones relevant to this pull request. Please read the Contributing guidelines.

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@algorithms-keeper algorithms-keeper bot added awaiting reviews This PR is ready to be reviewed and removed awaiting reviews This PR is ready to be reviewed labels Mar 26, 2026
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