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Refactor Heap into its own class
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3 files changed

+195
-169
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3 files changed

+195
-169
lines changed

‎src/GeomAlgoTest.hx

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -133,7 +133,7 @@ class GeomAlgoTest extends Sprite {
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// VISVALINGAM-WHYATT SIMPLIFICATION
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setSlot(0, 3);
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startTime = Timer.stamp();
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var simplifiedPolyVW = VisvalingamWhyatt.simplify(perimeter, SimplificationMethod.Ratio(.1));
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var simplifiedPolyVW = VisvalingamWhyatt.simplify(perimeter, SimplificationMethod.MaxPoints(simplifiedPolyRDP.length));
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trace('Visv-Whyatt : ${Timer.stamp() - startTime}');
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drawPoly(simplifiedPolyVW, X + clipRect.x, Y + clipRect.y);
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addChild(getTextField("Visv-Whyatt\n" + simplifiedPolyVW.length + " pts", X, Y));

‎src/hxGeomAlgo/Heap.hx

Lines changed: 190 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,190 @@
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/**
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* Heap implementation.
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*
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* Based on:
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*
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* @see http://en.wikipedia.org/wiki/Binary_heap (Binary Heap)
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* @see https://github.com/jonasmalacofilho/dheap (Haxe - Jonas Malaco Filho)
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*
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* @author azrafe7
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*/
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package hxGeomAlgo;
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import hxGeomAlgo.Debug;
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/** Heap elements must implement this interface. */
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interface Heapable<T> {
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/** Used internally by Heap. Do not modify. */
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var position:Int;
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/**
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* Returns the result of comparing `this` to `other`, where the result is expected to be:
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* less than zero if `this` < `other`
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* equal to zero if `this` == `other`
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* greater than zero if `this` > `other`
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*/
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function compare(other:T):Int;
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}
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/**
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* Heap implementation (over Array).
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*
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* Note: depending on the compare function (i.e. if it's ascending or descending),
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* it will act as a MinHeap or MaxHeap (meaning that `pop()` will return the smallest
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* or the largest element respectively).
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*
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* @author azrafe7
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*/
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class Heap<T:Heapable<T>>
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{
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private var data:Array<T>;
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public function new():Void
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{
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data = new Array<T>();
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}
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/** Number of elements in the Heap. */
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public var length(default, null):Int = 0;
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/** Inserts `obj` into the Heap. */
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public function push(obj:T):Void
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{
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var i = length;
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set(obj, i);
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length++;
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if (length > 1) bubbleUp(i);
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}
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/** Returns the root element (i.e. the smallest or largest, depending on compare()) and removes it from the Heap. Or null if the Heap is empty. */
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public function pop():T
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{
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if (length == 0) return null;
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var res = data[0];
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var len = length;
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var lastObj = data[len - 1];
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data[len - 1] = null;
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length--;
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if (len > 1) {
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set(lastObj, 0);
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bubbleDown(0);
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}
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return res;
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}
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/** Returns the root element (i.e. the smallest or largest, depending on compare()) without removing it from the Heap. Or null if the Heap is empty. */
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public function top():T
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{
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return length > 0 ? data[0] : null;
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}
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/** Removes `obj` from the Heap. Checks for correctness are only done in debug. */
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public function remove(obj:T):Int
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{
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var pos = obj.position;
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Debug.assert((pos >= 0 && pos < length), "Object not found.");
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Debug.assert(data[pos] == obj, '`obj` and retrieved object at $pos don\'t match.');
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var len = length;
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var lastObj = data[len - 1];
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data[len - 1] = null;
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length--;
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if (pos != len - 1) {
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set(lastObj, pos);
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lastObj.compare(obj) < 0 ? bubbleUp(pos) : bubbleDown(pos);
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}
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return pos;
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}
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inline public function clear():Void
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{
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#if (flash || js)
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untyped data.length = 0;
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#else
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data.splice(0, length);
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#end
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length = 0;
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}
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private function bubbleDown(i:Int):Void
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{
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var left = leftOf(i);
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var right = rightOf(i);
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var curr = i;
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if (left < length && data[left].compare(data[curr]) < 0) curr = left;
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if (right < length && data[right].compare(data[curr]) < 0) curr = right;
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if (curr != i) {
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swap(curr, i);
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bubbleDown(curr);
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}
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}
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private function bubbleUp(i:Int):Void
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{
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while (i > 0 && !(data[i].compare(data[parentOf(i)]) > 0)) {
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var parent = parentOf(i);
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swap(parent, i);
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i = parent;
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}
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}
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public function validate():Void
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{
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if (length > 0) _validate(0);
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}
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public function toArray():Array<T>
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{
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return [].concat(data);
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}
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private function _validate(i:Int):Void
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{
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var len = length;
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var left = leftOf(i);
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var right = rightOf(i);
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if (left < len) {
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Debug.assert(data[i].compare(data[left]) <= 0, 'Broken heap invariant (parent@$i > leftChild@$left).');
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_validate(leftOf(i));
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}
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if (right < len) {
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Debug.assert(data[i].compare(data[right]) <= 0, 'Broken heap invariant (parent@$i > rightChild@$right).');
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_validate(rightOf(i));
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}
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}
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private function set(obj:T, index:Int):Void
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{
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data[index] = obj;
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obj.position = index;
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}
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inline private function leftOf(i:Int):Int
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{
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return 2 * i + 1;
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}
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inline private function rightOf(i:Int):Int
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{
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return 2 * i + 2;
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}
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inline private function parentOf(i:Int):Int
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{
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return (i - 1) >> 1;
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}
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inline private function swap(i:Int, j:Int):Void
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{
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var temp = data[i];
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set(data[j], i);
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set(temp, j);
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}
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}

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