Fix binary search bug #42
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WalkthroughAdds a new module implementing iterative binary search with correct right bound initialization, returning the index of the target or -1. Includes a simple print demonstration. Changes
Sequence Diagram(s)sequenceDiagram
actor Caller
participant BS as binary_search(arr, target)
Caller->>BS: call(arr, target)
loop while left <= right
BS->>BS: mid = (left + right) // 2
alt arr[mid] == target
BS-->>Caller: return mid
else arr[mid] < target
BS->>BS: left = mid + 1
else arr[mid] > target
BS->>BS: right = mid - 1
end
end
BS-->>Caller: return -1
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🔍 Automated Review for PR #42
Title: Fix binary search bug
🤖 Heuristic Analysis
buggy_binary_search.py:
- 🐛 Debug print statement found in buggy_binary_search.py
🧠 AI Analysis
Summary:
The pull request fixes a bug in the binary search implementation and adds a test case for functionality.
Suggestions:
- Remove the debug print statement at the end of the file to maintain clean code.
- Consider adding more test cases to cover edge cases, such as searching for a target that is not in the array or testing with an empty array.
- Include a docstring for the
binary_searchfunction to explain its parameters and return value for better documentation. - Ensure that the function handles cases where the input array is not sorted, as binary search requires a sorted array.
- Consider using type hints for the function parameters and return type to improve code readability and maintainability.
🤖 This review was generated automatically by GraphBit PR Reviewer
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Actionable comments posted: 1
🧹 Nitpick comments (4)
buggy_binary_search.py (4)
2-2: Remove change-log style inline comment.Keep commit history in git; avoid “Bug fixed …” comments in code.
- left, right = 0, len(arr) - 1 # Bug fixed: use len(arr) - 1 + left, right = 0, len(arr) - 1
1-1: Add return annotation and a brief docstring.Clarifies contract (sorted ascending, -1 when absent).
-def binary_search(arr, target): +def binary_search(arr, target) -> int: + """Return index of target in ascending-sorted arr, or -1 if not found."""
1-11: Optional: lean on bisect for a concise, battle-tested implementation.Keeps behavior while reducing code surface.
-def binary_search(arr, target): - left, right = 0, len(arr) - 1 - while left <= right: - mid = (left + right) // 2 - if arr[mid] == target: - return mid - elif arr[mid] < target: - left = mid + 1 - else: - right = mid - 1 - return -1 +import bisect + +def binary_search(arr, target) -> int: + """Return index of target in ascending-sorted arr, or -1 if not found.""" + i = bisect.bisect_left(arr, target) + return i if i != len(arr) and arr[i] == target else -1
1-11: Add tests for edge cases.Recommend cases: empty list, single element miss/hit, first/last element, duplicates, not-found below/above range.
Do you want me to add a minimal unittest/pytest file covering these?
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📒 Files selected for processing (1)
buggy_binary_search.py(1 hunks)
🔇 Additional comments (1)
buggy_binary_search.py (1)
3-11: Binary search fix looks correct.Iterative logic and bounds are correct; handles empty input and returns -1 when not found.
| right = mid - 1 | ||
| return -1 | ||
|
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| print(binary_search([1, 2, 3, 4, 5], 3)) |
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🛠️ Refactor suggestion
Avoid top-level side effects; gate the demo under main.
Prevents output on import.
-print(binary_search([1, 2, 3, 4, 5], 3))
+if __name__ == "__main__":
+ print(binary_search([1, 2, 3, 4, 5], 3))📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| print(binary_search([1, 2, 3, 4, 5], 3)) | |
| if __name__ == "__main__": | |
| print(binary_search([1, 2, 3, 4, 5], 3)) |
🤖 Prompt for AI Agents
In buggy_binary_search.py around line 13, the direct call
print(binary_search([1, 2, 3, 4, 5], 3)) causes a top-level side effect on
import; move this demo into a guarded main block by creating a small main() (or
similar) that performs the call and printing, then wrap the invocation with if
__name__ == "__main__": main() so importing the module no longer produces
output.
|
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This PR fixes the binary search bug in buggy_binary_search.py.
Summary by CodeRabbit