fix(data_structures): handle exact prefix match in RadixNode.insert to fix IndexError (#11316)#14835
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…gorithms#7854) The split() function in treap.py uses `<` comparison but the docstring states that the right subtree should contain values "greater or equal" to the split value. This fix changes `elif value < root.value:` to `elif value <= root.value:` so that equal values go to the right subtree as documented. Fixes TheAlgorithms#7854
…o fix IndexError Fixes TheAlgorithms#11316 The insert() method's Case 3 (remaining_prefix == "") would call self.nodes[matching_string[0]].insert(remaining_word) even when remaining_word is empty string. This causes an IndexError in Case 2 when word[0] is accessed on an empty string. Fix: Check if remaining_word is non-empty before recursing. If remaining_word is empty, it means the inserted word exactly matches the prefix of the incoming node, so we just mark that node as a leaf. Also adds a doctest for the reported scenario: insert('fooaaa'), insert('foobbb'), insert('foo') And adds assertions to test_trie() to cover this case.
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Describe your change:
Fixes #11316
Fixes an
IndexErrorwhen inserting a word that is a prefix of an already-inserted word (e.g. inserting"foo"after"fooaaa"and"foobbb").Root cause: In
insert(), Case 3 (remaining_prefix == "") unconditionally calledself.nodes[matching_string[0]].insert(remaining_word)even whenremaining_wordwas"". The recursive call then hit Case 2 which accessedword[0]on an empty string, raisingIndexError: string index out of range.Fix: Check
if remaining_word:before recursing. Whenremaining_wordis empty the inserted word exactly matches the incoming node's prefix, so we mark that nodeis_leaf = Truedirectly.Checklist:
Fixes: #11316.