Fix ListDictionaryInternal.Count to not be O(n)#123899
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stephentoub merged 1 commit intodotnet:mainfrom Feb 2, 2026
Merged
Fix ListDictionaryInternal.Count to not be O(n)#123899stephentoub merged 1 commit intodotnet:mainfrom
stephentoub merged 1 commit intodotnet:mainfrom
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Rarely used but also unnecessary.
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MihaZupan
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Feb 2, 2026
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Pull request overview
This PR optimizes the Count property of the nested NodeKeyValueCollection class within ListDictionaryInternal by eliminating an unnecessary O(n) traversal. The ListDictionaryInternal class already maintains a count field that is incremented on Add operations and decremented on Remove operations, accessible through the public Count property (line 83). The nested collection's ICollection.Count implementation was unnecessarily iterating through all nodes to compute the count, when it could simply delegate to the parent list's already-tracked count.
Changes:
- Simplified
NodeKeyValueCollection.ICollection.Countfrom an O(n) implementation that traverses the linked list to an O(1) property that returnslist.Count
This was referenced Feb 3, 2026
lewing
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Rarely used but also unnecessary.
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Rarely used but also unnecessary.