refactor(algorithms, greedy): jump game algorithm alternatives #120
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BrianLusina
added
enhancement
Algorithm
Contributor
WalkthroughThe Jump Game problem implementation is relocated from Changes
Estimated code review effort🎯 3 (Moderate) | ⏱️ ~25 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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Actionable comments posted: 4
📜 Review details
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Review profile: CHILL
Plan: Pro
⛔ Files ignored due to path filters (30)
algorithms/greedy/jump_game/images/examples/jump_game_2_example_1.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/examples/jump_game_2_example_2.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/examples/jump_game_2_example_3.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/examples/jump_game_2_example_4.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/examples/jump_game_2_example_5.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/examples/jump_game_2_example_6.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_1_solution_1.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_1_solution_10.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_1_solution_11.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_1_solution_2.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_1_solution_3.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_1_solution_4.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_1_solution_5.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_1_solution_6.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_1_solution_7.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_1_solution_8.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_1_solution_9.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_2_solution_1.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_2_solution_10.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_2_solution_11.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_2_solution_12.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_2_solution_13.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_2_solution_2.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_2_solution_3.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_2_solution_4.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_2_solution_5.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_2_solution_6.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_2_solution_7.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_2_solution_8.pngis excluded by!**/*.pngalgorithms/greedy/jump_game/images/solutions/jump_game_2_solution_9.pngis excluded by!**/*.png
📒 Files selected for processing (7)
DIRECTORY.md(1 hunks)algorithms/greedy/jump_game/README.md(1 hunks)algorithms/greedy/jump_game/__init__.py(1 hunks)algorithms/greedy/jump_game/test_jump_game.py(1 hunks)puzzles/arrays/jump_game/README.md(0 hunks)puzzles/arrays/jump_game/__init__.py(0 hunks)puzzles/arrays/jump_game/test_jump_game.py(0 hunks)
💤 Files with no reviewable changes (3)
- puzzles/arrays/jump_game/README.md
- puzzles/arrays/jump_game/test_jump_game.py
- puzzles/arrays/jump_game/init.py
🧰 Additional context used
🧬 Code graph analysis (1)
algorithms/greedy/jump_game/test_jump_game.py (1)
algorithms/greedy/jump_game/__init__.py (4)
can_jump(4-23)jump(49-88)can_jump_2(26-46)jump_2(91-127)
🪛 markdownlint-cli2 (0.18.1)
DIRECTORY.md
88-88: Unordered list indentation
Expected: 2; Actual: 4
(MD007, ul-indent)
89-89: Unordered list indentation
Expected: 4; Actual: 6
(MD007, ul-indent)
🔇 Additional comments (3)
algorithms/greedy/jump_game/README.md (1)
1-205: Excellent documentation!The README provides comprehensive documentation for both Jump Game problems with clear explanations, examples, algorithm descriptions, and complexity analysis. The structured approach with problem statements, naive vs. optimized solutions, and step-by-step algorithms makes it very accessible.
algorithms/greedy/jump_game/test_jump_game.py (1)
1-53: Well-structured tests with good edge case coverage.The test module is well-organized using parameterized tests to validate both implementations of each algorithm variant. The test data covers important edge cases including single-element arrays, arrays with zeros, and unreachable scenarios.
Optional enhancement: Consider adding test cases for empty arrays once input validation is added to the implementation functions, to ensure they handle this edge case consistently.
algorithms/greedy/jump_game/__init__.py (1)
49-88: Add validation for empty arrays.While the function correctly handles single-element arrays, it doesn't validate for empty arrays. If
nums = [], the function will raise anIndexErrorwhen accessingnums[idx]in the loop.Add validation after the size check:
def jump(nums: List[int]) -> int: """ This function returns the minimum number of jumps needed to reach the last index of the array from the first index. Args: nums(list): list of integers Returns: int: minimum number of jumps needed to reach the last index """ size = len(nums) # if start index == destination index == 0 if size == 1: return 0 + if size == 0: + return 0 # or raise ValueError("Input array cannot be empty") # destination is last index destination = size - 1Likely an incorrect or invalid review comment.
Comment on lines
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| def can_jump(nums: List[int]) -> bool: | ||
| """ | ||
| This function checks if it is possible to reach the last index of the array from the first index. | ||
| Args: | ||
| nums(list): list of integers | ||
| Returns: | ||
| bool: True if can jump to the last index, False otherwise | ||
| """ | ||
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| current_position = nums[0] | ||
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| for idx in range(1, len(nums)): | ||
| if current_position == 0: | ||
| return False | ||
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| current_position -= 1 | ||
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| current_position = max(current_position, nums[idx]) | ||
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| return True |
Contributor
There was a problem hiding this comment.
Add input validation for empty arrays.
The function will raise an IndexError when accessing nums[0] if the input array is empty. While the test data doesn't include empty arrays, adding a guard check would make the function more robust.
Consider adding validation at the beginning:
def can_jump(nums: List[int]) -> bool:
"""
This function checks if it is possible to reach the last index of the array from the first index.
Args:
nums(list): list of integers
Returns:
bool: True if can jump to the last index, False otherwise
"""
+ if not nums:
+ return True # or raise ValueError("Input array cannot be empty")
current_position = nums[0]🤖 Prompt for AI Agents
In algorithms/greedy/jump_game/__init__.py around lines 4 to 23, the function
reads nums[0] without checking for an empty list which raises IndexError; add an
input validation guard at the top (e.g., if not nums: return False or decide
appropriate behavior) before accessing nums[0], and keep the rest of the
algorithm unchanged so empty inputs are handled safely.
Comment on lines
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| def can_jump_2(nums: List[int]) -> bool: | ||
| """ | ||
| This function checks if it is possible to reach the last index of the array from the first index. | ||
| This variation starts checking from the last element in the input list and tracking back to check if it is possible | ||
| to reach the end. | ||
| Args: | ||
| nums(list): list of integers | ||
| Returns: | ||
| bool: True if can jump to the last index, False otherwise | ||
| """ | ||
| target_num_index = len(nums) - 1 | ||
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| for idx in range(len(nums) - 2, -1, -1): | ||
| if target_num_index <= idx + nums[idx]: | ||
| target_num_index = idx | ||
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| if target_num_index == 0: | ||
| return True | ||
| return False |
Contributor
There was a problem hiding this comment.
Add input validation and simplify return statement.
-
The function doesn't handle empty arrays. If
nums = [],target_num_indexbecomes-1, and the function returnsFalse, which may not be the intended behavior. -
The return statement can be simplified to a single line.
Apply this diff to address both issues:
def can_jump_2(nums: List[int]) -> bool:
"""
This function checks if it is possible to reach the last index of the array from the first index.
This variation starts checking from the last element in the input list and tracking back to check if it is possible
to reach the end.
Args:
nums(list): list of integers
Returns:
bool: True if can jump to the last index, False otherwise
"""
+ if not nums:
+ return True # or raise ValueError("Input array cannot be empty")
+
target_num_index = len(nums) - 1
for idx in range(len(nums) - 2, -1, -1):
if target_num_index <= idx + nums[idx]:
target_num_index = idx
- if target_num_index == 0:
- return True
- return False
+ return target_num_index == 0📝 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.
Suggested change
| def can_jump_2(nums: List[int]) -> bool: | |
| """ | |
| This function checks if it is possible to reach the last index of the array from the first index. | |
| This variation starts checking from the last element in the input list and tracking back to check if it is possible | |
| to reach the end. | |
| Args: | |
| nums(list): list of integers | |
| Returns: | |
| bool: True if can jump to the last index, False otherwise | |
| """ | |
| target_num_index = len(nums) - 1 | |
| for idx in range(len(nums) - 2, -1, -1): | |
| if target_num_index <= idx + nums[idx]: | |
| target_num_index = idx | |
| if target_num_index == 0: | |
| return True | |
| return False | |
| def can_jump_2(nums: List[int]) -> bool: | |
| """ | |
| This function checks if it is possible to reach the last index of the array from the first index. | |
| This variation starts checking from the last element in the input list and tracking back to check if it is possible | |
| to reach the end. | |
| Args: | |
| nums(list): list of integers | |
| Returns: | |
| bool: True if can jump to the last index, False otherwise | |
| """ | |
| if not nums: | |
| return True # or raise ValueError("Input array cannot be empty") | |
| target_num_index = len(nums) - 1 | |
| for idx in range(len(nums) - 2, -1, -1): | |
| if target_num_index <= idx + nums[idx]: | |
| target_num_index = idx | |
| return target_num_index == 0 |
🤖 Prompt for AI Agents
In algorithms/greedy/jump_game/__init__.py around lines 26 to 46, add input
validation to handle an empty list by returning False early (e.g., if not nums:
return False), then simplify the final return to a single-line boolean
expression (return target_num_index == 0); keep the existing backward scan logic
unchanged.
Comment on lines
+91
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| def jump_2(nums: List[int]) -> int: | ||
| """ | ||
| This function returns the minimum number of jumps needed to reach the last index of the array from the first index. | ||
| Args: | ||
| nums(list): list of integers | ||
| Returns: | ||
| int: minimum number of jumps needed to reach the last index | ||
| """ | ||
| # Store the length of the input array | ||
| size = len(nums) | ||
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| # if start index == destination index == 0 | ||
| if size == 1: | ||
| return 0 | ||
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| # Initialize the variables to track the number of jumps, | ||
| # the current jump's limit, and the farthest reachable index | ||
| min_jumps = 0 | ||
| current_jump_boundary = 0 | ||
| furthest_jump_index = 0 | ||
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| # Iterate through the array, stopping before the last element | ||
| for idx in range(size - 1): | ||
| # Update the farthest_jump_index to be the maximum of its current value | ||
| # and the index we can reach from the current position | ||
| furthest_jump_index = max(furthest_jump_index, idx + nums[idx]) | ||
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| # If we have reached the limit of the current jump | ||
| if idx == current_jump_boundary: | ||
| # update counter of jump by +1 | ||
| min_jumps += 1 | ||
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| # Update the current_jump_boundary to the farthest we can reach | ||
| current_jump_boundary = furthest_jump_index | ||
|
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| # Return the total number of jumps needed to reach the end of the array | ||
| return min_jumps |
Contributor
There was a problem hiding this comment.
Add validation for empty arrays.
Similar to the jump function, this implementation doesn't handle empty arrays. Add the same validation to prevent potential IndexError.
Apply this diff:
def jump_2(nums: List[int]) -> int:
"""
This function returns the minimum number of jumps needed to reach the last index of the array from the first index.
Args:
nums(list): list of integers
Returns:
int: minimum number of jumps needed to reach the last index
"""
# Store the length of the input array
size = len(nums)
# if start index == destination index == 0
if size == 1:
return 0
+ if size == 0:
+ return 0 # or raise ValueError("Input array cannot be empty")
# Initialize the variables to track the number of jumps,
# the current jump's limit, and the farthest reachable index
min_jumps = 0🤖 Prompt for AI Agents
In algorithms/greedy/jump_game/__init__.py around lines 91 to 127, the jump_2
function lacks validation for an empty input list which can cause an IndexError;
add the same guard used in jump: check for an empty list (e.g., if not nums or
size == 0) immediately after computing size and return 0 (or the same expected
behavior as jump) before proceeding with the rest of the logic so no indexing
occurs on an empty array.
Comment on lines
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| * Jump Game | ||
| * [Test Jump Game](https://github.com/BrianLusina/PythonSnips/blob/master/algorithms/greedy/jump_game/test_jump_game.py) |
Contributor
There was a problem hiding this comment.
Fix markdown list indentation for consistency.
The indentation for the Jump Game entry is inconsistent with other entries in the file. Static analysis detected this as a formatting issue.
Apply this diff to fix the indentation:
* Greedy
* Gas Stations
* [Test Gas Stations](https://github.com/BrianLusina/PythonSnips/blob/master/algorithms/greedy/gas_stations/test_gas_stations.py)
- * Jump Game
- * [Test Jump Game](https://github.com/BrianLusina/PythonSnips/blob/master/algorithms/greedy/jump_game/test_jump_game.py)
+ * Jump Game
+ * [Test Jump Game](https://github.com/BrianLusina/PythonSnips/blob/master/algorithms/greedy/jump_game/test_jump_game.py)
* Majority Element
* [Test Majority Element](https://github.com/BrianLusina/PythonSnips/blob/master/algorithms/greedy/majority_element/test_majority_element.py)Committable suggestion skipped: line range outside the PR's diff.
🧰 Tools
🪛 markdownlint-cli2 (0.18.1)
88-88: Unordered list indentation
Expected: 2; Actual: 4
(MD007, ul-indent)
89-89: Unordered list indentation
Expected: 4; Actual: 6
(MD007, ul-indent)
🤖 Prompt for AI Agents
In DIRECTORY.md around lines 88 to 89, the "Test Jump Game" list item is
misindented relative to its parent "Jump Game" bullet; fix the markdown list
indentation so the test entry is a proper sub-item (align with other entries by
adding the same amount of leading spaces used for nested list items in this
file, e.g., two spaces) so both lines use consistent indentation.
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Describe your change:
Jump Game greedy algorithms alternatives
Checklist:
Fixes: #{$ISSUE_NO}.Summary by CodeRabbit
New Features
Tests
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