fix: heap Max() and PopLast() return wrong element#20
Open
suykerbuyk wants to merge 1 commit into
Open
Conversation
In a binary min-heap, the last array element is not necessarily the maximum. Max() must scan the leaf nodes (indices n/2..n-1) to find the true maximum. PopLast() used Remove(Len()-1) which removed an arbitrary element instead of the worst. This caused incorrect evictions during neighbor selection and search result trimming, degrading graph quality.
This was referenced Apr 11, 2026
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
Max()returneddata[len-1], which is not the maximum in a binary min-heapPopLast()calledRemove(Len()-1), removing an arbitrary element instead of the worstFix: scan leaf nodes (indices
n/2..n-1) to find the true maximum.Test plan
TestHeap_MaxAndPopLast— pushes known values, asserts Max/PopLast return the largestTestGraph_AddSearch— expected results now reflect correct eviction behaviorgo test ./...andgo vet ./...pass