public int MinMeetingRooms(Interval[] intervals)
{
Array.Sort(intervals, new Comparison <Interval>((i1, i2) => i2.start.CompareTo(i1.start)));
var rooms = new MinHeap(int.MaxValue);
foreach (var interval in intervals)
{
if (rooms.PeekMin() <= interval.start)
{
rooms.ExtractMin();
rooms.InsertKey(interval.end);
}
else
{
rooms.InsertKey(interval.end);
}
}
return(rooms._data.Count);
}
// head1 -> 1 -> 2 -> 3
// head2 -> 7 -> 9 -> 11
// head3 -> 4 -> 6 -> 10
public ListNode MergeKLists(ListNode[] lists)
{
var dummyHead = new ListNode(-1);
var runner = dummyHead;
var minHeap = new MinHeap();
for (var head = 0; head < lists.Length; head++)
{
if (lists[head] != null)
{
minHeap.Insert(new HeapItem()
{
data = lists[head].val,
listIndex = head
});
lists[head] = lists[head].next;
}
}
while (minHeap.Count() > 0)
{
var minFromHeap = minHeap.ExtractMin();
var minItemListNextNode = lists[minFromHeap.listIndex];
if (minItemListNextNode != null)
{
minHeap.Insert(new HeapItem()
{
data = minItemListNextNode.val,
listIndex = minFromHeap.listIndex
});
lists[minFromHeap.listIndex] = lists[minFromHeap.listIndex].next;
}
var node = new ListNode(minFromHeap.data);
runner.next = node;
runner = runner.next;
}
return(dummyHead.next);
}