Data update

Task/Sorting-algorithms-Heapsort/Groovy/sorting-algorithms-heapsort-2.groovy

@@ -1,2 +1,50 @@
-println (heapSort([23,76,99,58,97,57,35,89,51,38,95,92,24,46,31,24,14,12,57,78,4]))
-println (heapSort([88,18,31,44,4,0,8,81,14,78,20,76,84,33,73,75,82,5,62,70,12,7,1]))
+def makeSwap (list, element1, element2) {
+    //exchanges two elements in a list.
+    //print a dot for each swap.
+    print "."
+    list[[element2,element1]] = list[[element1,element2]]
+}
+
+def checkSwap (list, child, parent) {
+    //check if parent is smaller than child, then swap.
+    if (list[parent] < list[child]) makeSwap(list, child, parent)
+}
+
+def siftDown (list, start, end) {
+    //end represents the limit of how far down the heap to sift
+    //start is the head of the heap
+    def parent = start
+    while (parent*2 < end) { //While the root has at least one child
+        def child = parent*2 + 1 //root*2+1 points to the left child
+        //find the child with the higher value
+        //if the child has a sibling and the child's value is less than its sibling's..
+        if (child + 1 <= end && list[child] < list[child+1]) child++  //point to the other child
+        if (checkSwap(list, child, parent)) {  //check if parent is smaller than child and swap
+            parent = child                  //make child to next parent
+        } else {
+            return                          //The rest of the heap is in order - return.
+        }
+    }
+}
+
+def heapify (list) {
+    // Create a heap out of a list
+    // run through all the heap parents and
+    // ensure that each parent is lager than the child for all parent/childs.
+    // (list.size() -2) / 2 = last parent in the heap.
+    for (start in ((list.size()-2).intdiv(2))..0 ) {
+        siftDown(list, start, list.size() - 1)
+    }
+}
+
+def heapSort (list) {
+    //heap sort any unsorted list
+    heapify(list)  //ensure that the list is in a binary heap state
+    //Run the list backwards and
+    //for end = (size of list -1 ) to 0
+    for (end in (list.size()-1)..0 ) {
+        makeSwap(list, 0, end)    //put the top of the heap to the end (largest element)
+        siftDown(list, 0, end-1)    //ensure that the rest is a heap again
+    }
+    list
+}

Task/Sorting-algorithms-Heapsort/Groovy/sorting-algorithms-heapsort-3.groovy

@@ -0,0 +1,2 @@
+println (heapSort([23,76,99,58,97,57,35,89,51,38,95,92,24,46,31,24,14,12,57,78,4]))
+println (heapSort([88,18,31,44,4,0,8,81,14,78,20,76,84,33,73,75,82,5,62,70,12,7,1]))