RosettaCodeData/Task/Priority-queue/PicoLisp/priority-queue-1.l

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# Insert item into priority queue
(de insertPQ (Queue Prio Item)
(idx Queue (cons Prio Item) T) )
# Remove and return top item from priority queue
(de removePQ (Queue)
(cdar (idx Queue (peekPQ Queue) NIL)) )
# Find top element in priority queue
(de peekPQ (Queue)
(let V (val Queue)
(while (cadr V)
(setq V @) )
(car V) ) )
# Merge second queue into first
(de mergePQ (Queue1 Queue2)
(balance Queue1 (sort (conc (idx Queue1) (idx Queue2)))) )