feat(strings, trie): is prefix of word #108
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This adds a function `is_prefix_of_word` that enables searching for the index of a `search_word` in a given sentence and return the index if it exists. The index is 1-based. This modifies the `TrieNode` allowing callers to use the `TrieNode` to build a trie from the node and perform prefix searches a well as modifies the `Trie` class as well adding modifications and optimizations that match the changes in the `TrieNode` class. Also note that this change includes an `index` to the `TrieNode` to track the earliest index of a given character in a sentence. That is, what is the earliest that a word has been seen, This allows returning multiple words in the case of using the `Trie` `search` functionality.
BrianLusina
added
enhancement
Algorithm
|
Caution Review failedThe pull request is closed. WalkthroughAdds a new "Is Prefix" feature under pystrings with implementation, tests, and README; enhances the Trie and TrieNode to track and return word indices; updates a README image path, adds a happy number test, and a minor comment wording fix. Changes
Sequence Diagram(s)sequenceDiagram
participant Caller
participant API as is_prefix_of_word
participant Trie as Trie/TrieNode
Caller->>API: is_prefix_of_word(sentence, search_word)
API->>Trie: create root TrieNode
loop insert each word with 1-based index
API->>Trie: insert(word, index)
Trie->>Trie: traverse chars, set node.index = min(node.index, index)
Trie->>Trie: mark end_of_word
end
API->>Trie: search_prefix(search_word)
alt path exists for all chars
Trie-->>API: return node.index (or -1 if unset)
else missing char
Trie-->>API: return -1
end
API-->>Caller: return index or -1
Estimated code review effort🎯 3 (Moderate) | ⏱️ ~25 minutes
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✅ Passed checks (2 passed)
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Actionable comments posted: 3
🧹 Nitpick comments (1)
pystrings/is_prefix/test_is_prefix_of_word.py (1)
5-54: LGTM! Comprehensive test coverage.The test suite covers the key scenarios:
- Prefix matching at different positions (beginning, middle, end)
- No match cases returning -1
- Multiple words sharing a prefix (verifies earliest index is returned)
- Proper 1-based indexing
Consider adding edge case tests for completeness (though current coverage is good):
- Empty sentence or search_word
- search_word equals an entire word (not just prefix)
- Single-word sentence
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⛔ Files ignored due to path filters (18)
algorithms/fast_and_slow/happy_number/images/example/example_1_1.pngis excluded by!**/*.pngalgorithms/fast_and_slow/happy_number/images/example/example_1_2.pngis excluded by!**/*.pngalgorithms/fast_and_slow/happy_number/images/example/example_1_3.pngis excluded by!**/*.pngalgorithms/fast_and_slow/happy_number/images/example/example_2_1.pngis excluded by!**/*.pngalgorithms/fast_and_slow/happy_number/images/example/example_2_2.pngis excluded by!**/*.pngalgorithms/fast_and_slow/happy_number/images/example/example_2_3.pngis excluded by!**/*.pngalgorithms/fast_and_slow/happy_number/images/solution/solution_example_1.pngis excluded by!**/*.pngalgorithms/fast_and_slow/happy_number/images/solution/solution_example_2.pngis excluded by!**/*.pngalgorithms/fast_and_slow/happy_number/images/solution/solution_example_3.pngis excluded by!**/*.pngalgorithms/fast_and_slow/happy_number/images/solution/solution_example_4.pngis excluded by!**/*.pngalgorithms/fast_and_slow/happy_number/images/solution/solution_example_5.pngis excluded by!**/*.pngalgorithms/fast_and_slow/happy_number/images/solution/solution_example_6.pngis excluded by!**/*.pngalgorithms/fast_and_slow/happy_number/images/solution/solution_example_7.pngis excluded by!**/*.pngalgorithms/fast_and_slow/happy_number/images/solution/solution_example_8.pngis excluded by!**/*.pngpystrings/is_prefix/images/examples/is_prefix_example_1.pngis excluded by!**/*.pngpystrings/is_prefix/images/examples/is_prefix_example_2.pngis excluded by!**/*.pngpystrings/is_prefix/images/examples/is_prefix_example_3.pngis excluded by!**/*.pngpystrings/is_prefix/images/examples/is_prefix_example_4.pngis excluded by!**/*.png
📒 Files selected for processing (9)
DIRECTORY.md(1 hunks)algorithms/fast_and_slow/happy_number/README.md(1 hunks)algorithms/fast_and_slow/happy_number/test_happy_number.py(1 hunks)datastructures/streams/stream_checker/__init__.py(1 hunks)datastructures/trees/trie/trie.py(3 hunks)datastructures/trees/trie/trie_node.py(2 hunks)pystrings/is_prefix/README.md(1 hunks)pystrings/is_prefix/__init__.py(1 hunks)pystrings/is_prefix/test_is_prefix_of_word.py(1 hunks)
🧰 Additional context used
🧬 Code graph analysis (5)
pystrings/is_prefix/__init__.py (2)
datastructures/trees/trie/trie_node.py (3)
TrieNode(5-62)insert(26-41)search_prefix(43-62)datastructures/trees/trie/trie.py (1)
insert(9-49)
pystrings/is_prefix/test_is_prefix_of_word.py (1)
pystrings/is_prefix/__init__.py (1)
is_prefix_of_word(4-23)
datastructures/trees/trie/trie.py (1)
datastructures/trees/trie/trie_node.py (2)
TrieNode(5-62)insert(26-41)
algorithms/fast_and_slow/happy_number/test_happy_number.py (1)
algorithms/fast_and_slow/happy_number/__init__.py (1)
is_happy_number_2(39-102)
datastructures/trees/trie/trie_node.py (1)
datastructures/trees/trie/trie.py (1)
insert(9-49)
🪛 LanguageTool
algorithms/fast_and_slow/happy_number/README.md
[style] ~33-~33: Using many exclamation marks might seem excessive (in this case: 8 exclamation marks for a text that’s 1193 characters long)
Context: ...images/solution/solution_example_1.png) 
🪛 markdownlint-cli2 (0.18.1)
DIRECTORY.md
710-710: Unordered list indentation
Expected: 0; Actual: 2
(MD007, ul-indent)
711-711: Unordered list indentation
Expected: 2; Actual: 4
(MD007, ul-indent)
🔇 Additional comments (9)
algorithms/fast_and_slow/happy_number/test_happy_number.py (1)
116-120: Test looks correct but appears unrelated to PR objectives.The test correctly verifies that 20 is not a happy number (it cycles: 20→4→16→37→58→89→145→42→20). However, this change seems unrelated to the PR objectives, which describe adding
is_prefix_of_wordfunctionality and Trie modifications.algorithms/fast_and_slow/happy_number/README.md (1)
18-40: Image path reorganization looks good but appears unrelated to PR objectives.The image paths have been appropriately updated to use an organized directory structure (images/example/ and images/solution/). However, like the test file changes, this documentation update seems unrelated to the PR objectives about adding
is_prefix_of_wordfunctionality and Trie modifications.Note: The static analysis hint about excessive exclamation marks is a false positive—these are Markdown image syntax (
), not punctuation.datastructures/streams/stream_checker/__init__.py (1)
61-61: LGTM! Minor grammar improvement.The hyphenation of "dead-end" as a compound adjective is grammatically correct and improves readability.
DIRECTORY.md (1)
710-711: LGTM! Documentation update for new feature.The new entries correctly document the "Is Prefix" feature and follow the existing structure and indentation pattern used throughout the file.
pystrings/is_prefix/README.md (1)
1-24: LGTM! Clear and comprehensive documentation.The README provides a well-structured problem description with constraints and examples. The explanation of prefix definition and return value semantics (1-based indexing, earliest match, -1 for no match) aligns well with the implementation.
pystrings/is_prefix/__init__.py (1)
4-23: LGTM! Clean and correct implementation.The function correctly:
- Builds a Trie from sentence words with 1-based indices (line 19)
- Delegates prefix search to the TrieNode implementation
- Returns the appropriate index or -1
The implementation is straightforward and matches the documented behavior.
datastructures/trees/trie/trie_node.py (2)
1-1: LGTM! Clean addition of index tracking.The new
indexattribute with proper typing and inclusion in__repr__provides good foundation for tracking word positions in the Trie.Also applies to: 21-21, 24-24
26-41: LGTM! Correct index tracking implementation.The
insertmethod properly maintains the minimum index along each character path usingcurr.index or float("inf")to handle the None case. This ensures that when multiple words share a prefix, the earliest word's index is preserved at each node.datastructures/trees/trie/trie.py (1)
88-89: LGTM! Helpful debugging addition.The
__repr__method provides a useful string representation that will recursively show the trie structure via the TrieNode's__repr__method.
…onSnips into feat/is-prefix-of-word rigin feat/is-
Describe your change:
This adds a function
is_prefix_of_wordthat enables searching for theindex of a
search_wordin a given sentence and return the index if itexists. The index is 1-based.
This modifies the
TrieNodeallowing callers to use theTrieNodetobuild a trie from the node and perform prefix searches a well as
modifies the
Trieclass as well adding modifications and optimizationsthat match the changes in the
TrieNodeclass.Also note that this change includes an
indexto theTrieNodetotrack the earliest index of a given character in a sentence. That is,
what is the earliest that a word has been seen, This allows returning
multiple words in the case of using the
Triesearchfunctionality.Checklist:
Fixes: #{$ISSUE_NO}.Summary by CodeRabbit
New Features
Documentation
Tests
Style
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