Add unique number finder script with input parsing#126
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Reviewer's GuideIntroduces a new Python script that reads integer inputs (with optional count prefix) from stdin, finds the single non-duplicated number using XOR, and includes a demo fallback when no input is provided. Sequence diagram for input parsing and unique number findingsequenceDiagram
participant User as actor User
participant Script as "uniqueNo.py"
participant Stdin as "stdin"
User->>Script: Run script
Script->>Stdin: Read input
alt Input provided
Script->>Script: parse_input()
Script->>Script: unique_number(arr)
Script->>User: Print unique number
else No input provided
Script->>Script: Use demo array
Script->>Script: unique_number(demo)
Script->>User: Print demo and unique number
end
Class diagram for functions in uniqueNo.pyclassDiagram
class unique_number {
+unique_number(arr: Iterable[int]) int
}
class parse_input {
+parse_input(stream) list
}
class main {
+main() int
}
unique_number <.. main : uses
parse_input <.. main : uses
File-Level Changes
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WalkthroughA new Python utility file is introduced implementing an algorithm to find the unique integer in an array where all other elements appear exactly twice. The implementation includes input parsing, XOR-based computation, and a command-line interface with demo mode. Changes
Sequence Diagram(s)sequenceDiagram
participant User
participant main as main()
participant parse as parse_input()
participant unique as unique_number()
User->>main: Run program
main->>parse: Request input
alt Input provided
parse->>User: Read from stdin
User-->>parse: Array of integers
parse-->>main: Return parsed list
else No input
main-->>main: Use demo array
end
main->>unique: Pass array
unique->>unique: Compute XOR accumulation
unique-->>main: Return unique value
main->>User: Print result
Estimated code review effort🎯 2 (Simple) | ⏱️ ~8 minutes
Poem
Pre-merge checks and finishing touches❌ Failed checks (1 warning)
✅ Passed checks (2 passed)
✨ Finishing touches
🧪 Generate unit tests (beta)
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PR Compliance Guide 🔍Below is a summary of compliance checks for this PR:
Compliance status legend🟢 - Fully Compliant🟡 - Partial Compliant 🔴 - Not Compliant ⚪ - Requires Further Human Verification 🏷️ - Compliance label |
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Hey there - I've reviewed your changes and they look great!
Prompt for AI Agents
Please address the comments from this code review:
## Individual Comments
### Comment 1
<location> `Python/uniqueNo.py:43-45` </location>
<code_context>
def parse_input(stream) -> list:
data = stream.read().strip().split()
if not data:
return []
try:
nums = [int(tok) for tok in data]
except ValueError:
raise
# If first token is count and matches remaining length, skip it
if len(nums) >= 2 and nums[0] == len(nums) - 1:
return nums[1:]
return nums
</code_context>
<issue_to_address>
**suggestion (code-quality):** We've found these issues:
- Lift code into else after jump in control flow ([`reintroduce-else`](https://docs.sourcery.ai/Reference/Default-Rules/refactorings/reintroduce-else/))
- Replace if statement with if expression ([`assign-if-exp`](https://docs.sourcery.ai/Reference/Default-Rules/refactorings/assign-if-exp/))
```suggestion
return nums[1:] if len(nums) >= 2 and nums[0] == len(nums) - 1 else nums
```
</issue_to_address>Help me be more useful! Please click 👍 or 👎 on each comment and I'll use the feedback to improve your reviews.
| if len(nums) >= 2 and nums[0] == len(nums) - 1: | ||
| return nums[1:] | ||
| return nums |
There was a problem hiding this comment.
suggestion (code-quality): We've found these issues:
- Lift code into else after jump in control flow (
reintroduce-else) - Replace if statement with if expression (
assign-if-exp)
| if len(nums) >= 2 and nums[0] == len(nums) - 1: | |
| return nums[1:] | |
| return nums | |
| return nums[1:] if len(nums) >= 2 and nums[0] == len(nums) - 1 else nums |
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Actionable comments posted: 1
🧹 Nitpick comments (2)
Python/uniqueNo.py (2)
37-40: Remove redundant exception handler.The
except ValueError: raiseblock is unnecessary since the exception is immediately re-raised without modification.Apply this diff:
try: nums = [int(tok) for tok in data] - except ValueError: - raise + except ValueError as e: + raise ValueError(f"Invalid input token: {e}") from eOr simply remove the try/except entirely and let the ValueError propagate naturally.
Based on static analysis hints.
48-62: Narrow the exception handler to catch specific exceptions.Catching broad
Exceptionat line 51 can mask unexpected errors. Sinceparse_inputraisesValueError, catch that specifically.Apply this diff:
def main() -> int: try: arr = parse_input(sys.stdin) - except Exception: + except ValueError as e: - print("Error: failed to parse input. Expected integers.") + print(f"Error: failed to parse input. {e}") return 1Based on static analysis hints.
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Review profile: CHILL
Plan: Pro
📒 Files selected for processing (1)
Python/uniqueNo.py(1 hunks)
🧰 Additional context used
🪛 Ruff (0.14.1)
Python/uniqueNo.py
39-40: Remove exception handler; error is immediately re-raised
(TRY203)
51-51: Do not catch blind exception: Exception
(BLE001)
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- GitHub Check: Sourcery review
🔇 Additional comments (3)
Python/uniqueNo.py (3)
1-19: LGTM! Clear documentation and minimal imports.The module docstring is comprehensive and the imports are appropriate for the functionality.
21-30: LGTM! Optimal XOR-based algorithm.The XOR approach is elegant and efficient for finding the unique element.
65-66: LGTM! Standard entry point pattern.Using
raise SystemExit(main())properly propagates the exit code.
| if len(nums) >= 2 and nums[0] == len(nums) - 1: | ||
| return nums[1:] |
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Critical bug: ambiguous count detection can remove the unique number.
The heuristic nums[0] == len(nums) - 1 cannot reliably distinguish between a count prefix and an actual array element. This causes incorrect results when the unique number happens to be the first element AND equals len(nums) - 1.
Example failure case:
- Input:
5 1 2 3 1 2(no count, unique number is 5) - After parsing: nums = [5, 1, 2, 3, 1, 2]
- Condition: nums[0] (5) == len(nums) - 1 (5) → True
- Result: skips first element → [1, 2, 3, 1, 2] → returns 3 (incorrect, should be 5)
Recommended fix: Remove the ambiguity by requiring a consistent input format. Choose one of:
- Always require a count prefix:
def parse_input(stream) -> list:
data = stream.read().strip().split()
- if not data:
+ if len(data) < 2:
return []
try:
nums = [int(tok) for tok in data]
except ValueError:
raise
- # If first token is count and matches remaining length, skip it
- if len(nums) >= 2 and nums[0] == len(nums) - 1:
- return nums[1:]
- return nums
+ # Always treat first token as count
+ count = nums[0]
+ if count != len(nums) - 1:
+ raise ValueError(f"Count mismatch: expected {count} elements, got {len(nums) - 1}")
+ return nums[1:]- Never use a count prefix:
def parse_input(stream) -> list:
data = stream.read().strip().split()
if not data:
return []
try:
nums = [int(tok) for tok in data]
except ValueError:
raise
-
- # If first token is count and matches remaining length, skip it
- if len(nums) >= 2 and nums[0] == len(nums) - 1:
- return nums[1:]
return numsUpdate the docstring accordingly.
Committable suggestion skipped: line range outside the PR's diff.
🤖 Prompt for AI Agents
In Python/uniqueNo.py around lines 43 to 44, the heuristic checking if nums[0]
== len(nums) - 1 is ambiguous and can drop a legitimate first element (e.g.,
when the unique number equals len(nums)-1); fix by removing the count-prefix
handling and always treat the input list as the full array (i.e., delete the
conditional that strips nums[0] and ensure all callers/parsing expect no leading
count), and update the module docstring to state that inputs must not include a
count prefix (or alternatively, if you prefer the opposite, mandate and parse a
required count prefix explicitly—pick one and make the code and docstring
consistent).
2 participants
Summary by Sourcery
Add a standalone Python script to identify the unique element in a list of integers by XORing all values, complete with flexible input parsing, error handling, and a demo mode.
New Features:
Summary by CodeRabbit