Added remove, swap, and sort to ArrayList

lick/collect/ArrayList.ck

@@ -197,4 +197,52 @@ public class ArrayList extends List
         }
         return result;
     }
+
+    fun void remove(int index) {
+        for (index => int i; i < size() - 1; i++) {
+            set(i, get(i+1));
+        }
+        values.size(size() - 1);
+    }
+
+    // QuickSort
+    fun void sort(Comparator c) {
+        quickSort(0, size() - 1, c);
+    }
+
+    fun void quickSort(int low, int high, Comparator c) {
+
+        if (low < high) {
+            partition(low, high, c) => int p;
+            quickSort(low, p, c);
+            quickSort(p + 1, high, c);
+        }
+    }
+
+    fun int partition(int low, int high, Comparator c) {
+        get(low) @=> Object pivot;
+        low - 1 => int i;
+        high + 1 => int j;
+        while (true) {
+            do {
+                1 +=> i;
+            } while (c.compare(get(i), pivot) < 0);
+
+            do {
+                j - 1 => j;
+            } while (c.compare(get(j), pivot) > 0);
+
+            if (i >= j) {
+                return j;
+            }
+            swap(i, j);
+        }
+    }
+
+    fun void swap(int a, int b) {
+        get(a) @=> Object temp;
+        set(a, get(b));
+        set(b, temp);
+    }
+
 }