RosettaCodeData/Task/Priority-queue/M2000-Interpreter/priority-queue-1.m2000

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Module UnOrderedArray {
Class PriorityQueue {
Private:
Dim Item()
many=0, level=0, first
cmp = lambda->0
Module Reduce {
if .many<.first*2 then exit
if .level<.many/2 then .many/=2 : Dim .Item(.many)
}
Public:
Module Clear {
Dim .Item() \\ erase all
.many<=0 \\ default
.Level<=0
}
Module Add {
if .level=.many then
if .many=0 then Error "Define Size First"
Dim .Item(.many*2)
.many*=2
end if
Read Item
if .level=0 then
.Item(0)=Item
else.If .cmp(.Item(0), Item)=-1 then \\ Item is max
.Item(.level)=Item
swap .Item(0), .Item(.level)
else
.Item(.level)=Item
end if
.level++
}
Function Peek {
if .level=0 then error "empty"
=.Item(0)
}
Function Poll {
if .level=0 then error "empty"
=.Item(0)
if .level=2 then
swap .Item(0), .Item(1)
.Item(1)=0
.Level<=1
else.If .level>2 then
.Level--
Swap .Item(.level), .Item(0)
.Item(.level)=0
for I=.level-1 to 1
if .cmp(.Item(I), .Item(I-1))=1 then Swap .Item(I), .Item(I-1)
next
else
.level<=0 : .Item(0)=0
end if
.Reduce
}
Module Remove {
if .level=0 then error "empty"
Read Item
k=true
if .cmp(.Item(0), Item)=0 then
Item=.Poll()
K~ \\ k=false
else.If .Level>1 then
I2=.Level-1
for I=1 to I2
if k then
if .cmp(.Item(I), Item)=0 then
if I<I2 then Swap .Item(I), .Item(I2)
.Item(I2)=0
k=false
end if
else
exit
end if
next
.Level--
end if
if k then Error "Not Found"
.Reduce
}
Function Size {
if .many=0 then Error "Define Size First"
=.Level
}
Class:
Module PriorityQueue {
if .many>0 then Error "Clear List First"
Read .many, .cmp
.first<=.many
Dim .Item(.many)
}
}
Class Item { X, S$
Class: // constructor as temporary definition
Module Item {Read .X, .S$}
}
Queue=PriorityQueue(100, Lambda -> {Read A,B : =Compare(A.X,B.X)})
Queue.Add Item(3, "Clear drains") : Gosub PrintTop()
Queue.Add Item(4 ,"Feed cat") : PrintTop()
Queue.Add Item(5 ,"Make tea") : PrintTop()
Queue.Add Item(1 ,"Solve RC tasks") : PrintTop()
Queue.Add Item(2 ,"Tax return") : PrintTop()
Print "remove items"
While true
MM=Queue.Poll() :Print MM.X, MM.S$,,"Size="; Queue.Size()
if Queue.Size()=0 then exit
PrintTop()
End While
Sub PrintTop()
M=Queue.Peek() : Print "Item ";M.X, M.S$
End Sub
}
UnOrderedArray