Priority queue: Difference between revisions

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 <syntaxhighlight lang="m2000 interpreter">
+// class definitions are global
+// if there aren't defintions in a class
+global countmany=0&
+class obj {
+      x, s$
+      property toString$ {
+            value (sp=8) {
+                  link parent x, s$ to x, s$
+                  value$=format$("{0::-5}"+string$(" ", sp)+"{1:20}", x, s$)
+            }
+      }
+      remove {
+            countmany--
+      }
+class:
+      module obj (.x, .s$) {countmany++}
+}
 Module PriorityQueueForGroups {
-      class obj {
-            x, s$
-      class:
-            module obj (.x, .s$) {}
-      }
       Flush  ' empty current stack
-      Data obj(3, "Clear drains"), obj(4 ,"Feed cat"), obj( 5 , "Make tea"), obj( 1 ,"Solve RC tasks"), obj( 2 , "Tax return")
+      Data obj(3, "Clear drains"), obj(4 ,"Feed cat"), obj( 5 , "Make tea")
+      Data obj( 1 ,"Solve RC tasks"), obj( 2 , "Tax return")
+      ObjectCount()
       b=stack
-      comp=lambda (a, b) ->{
+      while not empty
-                  =a.x<b.x
+            InsertPQ(b) // top of stack is b then objects follow
-      }
+      end while
-      module InsertPQ (a, n, &comp) {
+      ObjectCount()
+      Print "Using Peek to Examine Priority Queue"
-            if len(a)=0 then stack a {data n} : exit
+      n1=each(b)
-            if comp(n, stackitem(a)) then stack a {push n} : exit
-             stack a {
+      Header()
+      while n1
+            Print @Peek$(n1)
+      end while
+      ObjectCount()
+      Header()
+      while not @isEmpty(b)
+            Print @Pop(b)=>tostring$
+      end while
+      ObjectCount()
+      // here are the subs/simple functions
+      // these are static parts of module
+      sub Header()
+            Print " Priority        Task"
+            Print "==========  ================"
+      end sub
+      sub ObjectCount()
+            Print "There are ";countmany;" objects of type obj"
+      end sub
+      sub InsertPQ(a, n)
+            Print "Insert:";n.tostring$(1)
+            if len(a)=0 then stack a {data n} : exit sub
+            if @comp(n, stackitem(a)) then stack a {push n} : exit sub
+            stack a {
                   push n
-                  t=2: b=len(a)
+                  local t=2, b=len(a)
-                   m=b
+                  local m=b
-                   while t<=b {
+                  while t<=b
-                         t1=m
+                        t1=m
                         m=(b+t) div 2
                         if m=0 then  m=t1 : exit
-                        If comp(stackitem(m),n) then t=m+1:  continue
+                        If @comp(stackitem(m),n) then t=m+1:  continue
                         b=m-1
                         m=b
-                  }
+                  end while
                   if m>1 then shiftback m
             }
-      }
+      end sub
-      b=stack
+      function comp(a, b)
-      While not empty {
+            =a.x<b.x
+      end function
-            InsertPQ b, Group, &comp    ' Group pop a group from current stack
+      function Peek$(a as stack)
-      }
-       n1=each(b)
+            =stackitem(a)=>toString$
-      while n1 {
+            countmany++
-            m=stackitem(n1)
+      end function
+      function IsEmpty(a)
-            Print m.x, m.s$
-      }
+            =len(a)=0
+      end function
-      Function Peek$(a) {m=stackitem(a) : =m.s$}
-      Print Peek$(b)
+      Function Pop(a)
+            // Group make a copy
-      Function Pop$(a) {
+            stack a {=Group:countmany++}
-            stack a {
+      end function
-                  m=stackitem()
-                  =m.s$
-                   drop
-            }
-      }
-      Function IsEmpty(a) {
-              =len(a)=0
-      }
-      While not isEmpty(b) {
-            Print Pop$(b)
-      }
 }
 PriorityQueueForGroups