summaryrefslogtreecommitdiff
path: root/bin/ai/library/queue/binary_heap/main.nut
diff options
context:
space:
mode:
Diffstat (limited to 'bin/ai/library/queue/binary_heap/main.nut')
-rw-r--r--bin/ai/library/queue/binary_heap/main.nut131
1 files changed, 0 insertions, 131 deletions
diff --git a/bin/ai/library/queue/binary_heap/main.nut b/bin/ai/library/queue/binary_heap/main.nut
deleted file mode 100644
index 05fd452f3..000000000
--- a/bin/ai/library/queue/binary_heap/main.nut
+++ /dev/null
@@ -1,131 +0,0 @@
-/* $Id$ */
-
-/**
- * Binary Heap.
- * Peek and Pop always return the current lowest value in the list.
- * Sort is done on insertion and on deletion.
- */
-class Binary_Heap
-{
- _queue = null;
- _count = 0;
-
- constructor()
- {
- _queue = [];
- }
-
- /**
- * Insert a new entry in the list.
- * The complexity of this operation is O(ln n).
- * @param item The item to add to the list.
- * @param priority The priority this item has.
- */
- function Insert(item, priority);
-
- /**
- * Pop the first entry of the list.
- * This is always the item with the lowest priority.
- * The complexity of this operation is O(ln n).
- * @return The item of the entry with the lowest priority.
- */
- function Pop();
-
- /**
- * Peek the first entry of the list.
- * This is always the item with the lowest priority.
- * The complexity of this operation is O(1).
- * @return The item of the entry with the lowest priority.
- */
- function Peek();
-
- /**
- * Get the amount of current items in the list.
- * The complexity of this operation is O(1).
- * @return The amount of items currently in the list.
- */
- function Count();
-
- /**
- * Check if an item exists in the list.
- * The complexity of this operation is O(n).
- * @param item The item to check for.
- * @return True if the item is already in the list.
- */
- function Exists(item);
-};
-
-function Binary_Heap::Insert(item, priority)
-{
- /* Append dummy entry */
- _queue.append(0);
- _count++;
-
- local hole;
- /* Find the point of insertion */
- for (hole = _count - 1; hole > 0 && priority <= _queue[hole / 2][1]; hole /= 2)
- _queue[hole] = _queue[hole / 2];
- /* Insert new pair */
- _queue[hole] = [item, priority];
-
- return true;
-}
-
-function Binary_Heap::Pop()
-{
- if (_count == 0) return null;
-
- local node = _queue[0];
- /* Remove the item from the list by putting the last value on top */
- _queue[0] = _queue[_count - 1];
- _queue.pop();
- _count--;
- /* Bubble down the last value to correct the tree again */
- _BubbleDown();
-
- return node[0];
-}
-
-function Binary_Heap::Peek()
-{
- if (_count == 0) return null;
-
- return _queue[0][0];
-}
-
-function Binary_Heap::Count()
-{
- return _count;
-}
-
-function Binary_Heap::Exists(item)
-{
- /* Brute-force find the item (there is no faster way, as we don't have the priority number) */
- foreach (node in _queue) {
- if (node[0] == item) return true;
- }
-
- return false;
-}
-
-
-
-function Binary_Heap::_BubbleDown()
-{
- if (_count == 0) return;
-
- local hole = 1;
- local tmp = _queue[0];
-
- /* Start switching parent and child until the tree is restored */
- while (hole * 2 < _count + 1) {
- local child = hole * 2;
- if (child != _count && _queue[child][1] <= _queue[child - 1][1]) child++;
- if (_queue[child - 1][1] > tmp[1]) break;
-
- _queue[hole - 1] = _queue[child - 1];
- hole = child;
- }
- /* The top value is now at his new place */
- _queue[hole - 1] = tmp;
-}