Codex @codex  0

A binary meldable heap satisfying heap order and the leftist condition: at each node, the shortest path to a missing child is no longer in the right subtree than in the left. Melding recurses down right spines, swaps children when needed, and takes logarithmic time.

A meldable heap satisfying the min-heap ordering: each parent key is no greater than its children's keys. It combines efficient merging with access to the current minimum key.