RosettaCodeData/Task/Priority-queue/SAS/priority-queue-2.sas

111 lines
2.6 KiB
SAS

proc ds2;
package Heap / overwrite=yes;
dcl int _entryorder _size _len _entryOrders[1000];
dcl double _times[1000];
dcl varchar(20) _kinds[1000];
method init();
_entryOrder = 1;
_size = 1000;
_len = 0;
end;
method empty() returns int;
return(_len=0);
end;
method compare(int index1, int index2) returns int;
return(_times[index1] < _times[index2] or (_times[index1] = _times[index2] and _entryOrders[index1] < _entryOrders[index2]));
end;
method SetItem(int index, double _time, int entryOrder, varchar(20) kind);
_times[index] = _time;
_entryOrders[index] = entryOrder;
_kinds[index] = kind;
end;
method CopyItem(int ito, int ifrom);
_times[ito] = _times[ifrom];
_entryOrders[ito] = _entryOrders[ifrom];
_kinds[ito] = _kinds[ifrom];
end;
method SwapItem(int index1, int index2);
dcl double tempD;
dcl int tempI;
dcl varchar(20) tempC;
tempD = _times[index1]; _times[index1] = _times[index2]; _times[index2]= tempD;
tempI = _entryorders[index1]; _entryorders[index1] = _entryorders[index2]; _entryorders[index2]= tempI;
tempC = _kinds[index1]; _kinds[index1] = _kinds[index2]; _kinds[index2]= tempC;
end;
method Siftdown(int index);
dcl int parent done child;
parent = index;
done = 0;
do while (parent*2 <= _len and ^done);
child = parent*2;
if (child+1 <= _len and Compare(child+1,child)) then
child = child + 1;
if Compare(child,parent) then do;
SwapItem(child,parent);
parent = child;
end;
else done = 1;
end;
end;
method Siftup(int index);
dcl int parent child done tempI;
child = index;
done = 0;
do while(child>1 and ^done);
parent = floor(child/2);
if Compare(parent,child) then
done = 1;
else do;
SwapItem(child,parent);
tempI = child;
child = parent;
parent = tempI;
end;
end;
end;
method Pop();
_len = _len - 1;
if (_len>0) then do;
CopyItem(1,_len+1);
Siftdown(1);
end;
end;
method PeekTime() returns double;
return _times[1];
end;
method PeekKind() returns varchar(20);
return _kinds[1];
end;
method Push(double _time, varchar(20) kind);
if _len >= _size then do;
put 'ERROR: exceeded size of heap.';
stop;
end;
_len = _len + 1;
_entryOrder = _entryOrder + 1;
SetItem(_len, _time, _entryOrder, kind);
Siftup(_len);
end;
endpackage;
run;
data _null_;
dcl package Heap h();
method init();
dcl double _time;
dcl varchar(20) _kind;
h.init();
h.Push(3, 'Clear drains');
h.Push(4, 'Feed cat');
h.Push(5, 'Make tea');
h.Push(1, 'Solve RC tasks');
h.Push(2, 'Tax return');
do while(^h.empty());
_time = h.PeekTime();
_kind = h.PeekKind();
put _time _kind;
h.Pop();
end;
end;
enddata;
run;