// Please send updates for this code to: fred@gruntose.com -- Thanks, fred.
//////////////
-#include <stdio.h>
-//temp!
-
namespace algorithms {
/*
* merges two sorted arrays into a single sorted array.
*/
template<class type>
- basis::array<type> merge(basis::array<type> &first, basis::array<type> &second,
- bool reverse)
+ basis::array<type> merge(basis::array<type> &first, basis::array<type> &second, bool reverse)
{
basis::array<type> to_return;
// operate until we've consumed both of the arrays.
} else if (second.length() <= 0) {
to_return += first[0];
first.zap(0, 0);
- } else if ( (!reverse && (first[0] <= second[0]))
- || (reverse && (first[0] >= second[0]))) {
+ } else if ((!reverse && (first[0] <= second[0])) || (reverse && (first[0] >= second[0]))) {
// the first list has a better value to add next.
to_return += first[0];
first.zap(0, 0);
// reverse the sense of "reverse", since our algorithm expects a normal heap (with largest on top).
heap<type> hap(v, n, !reverse);
- //temp
-// printf("hey after heaping: %s\n", dump_list(v, n).s());
-
int end = n - 1;
while (end > 0) {
-
-//printf("moving value %d\n", (int)v[0]);
// a[0] is the root and largest value for a normal heap. The swap moves it to the real end of the list and takes it out of consideration.
hap.swap_values(end, 0);
// reduce the heap size by 1.
//////////////
+ //! swaps the values in the array stored at positions a and b.
template<class type>
- void partition(type v[], int start, int end)
+ void swap_values(type array[], int a, int b)
{
+ type temp = array[a];
+ array[a] = array[b];
+ array[b] = temp;
+ }
+ // hoare's partition implementation.
+ template<class type>
+ int partition(type a[], int start, int end, bool reverse)
+ {
+// printf("before partition: %s\n", dump_list(a + start, end - start + 1).s());
+ int pivot = a[start];
+ int i = start - 1;
+ int j = end + 1;
+ while (true) {
+ do {
+ i++;
+ } while ((!reverse && (a[i] < pivot)) || (reverse && (a[i] > pivot)));
+ do {
+ j--;
+ } while ((!reverse && (a[j] > pivot)) || (reverse && (a[j] < pivot)));
+
+ if (i >= j) {
+// printf("after partition: %s\n", dump_list(a + start, end - start + 1).s());
+ return j;
+ }
+ swap_values(a, i, j);
+ }
}
-//! the recursive version of quick sort that does the work for our convenience method.
+ //! the recursive version of quick sort that does the work for our convenience method.
template<class type>
- void inner_quick_sort(type v[], int n, int start, int end, bool reverse = false)
+ void inner_quick_sort(type v[], int start, int end, bool reverse)
{
- if (start >= end) {
- // nothing to see here.
- } else {
+ if (start < end) {
// figure out where to pivot, and sort both halves around the pivot index.
- int pivot = partition(v, start, end);
- quicksort(v, start, pivot - 1);
- quicksort(v, pivot + 1, end);
+ int pivot = partition(v, start, end, reverse);
+ inner_quick_sort(v, start, pivot, reverse);
+ inner_quick_sort(v, pivot + 1, end, reverse);
}
}
template<class type>
void quick_sort(type v[], int n, bool reverse = false)
{
- inner_quick_sort(v, n, 0, n - 1, reverse);
+ inner_quick_sort(v, 0, n - 1, reverse);
}
} // namespace.
using namespace timely;
using namespace unit_test;
-const int MAX_ELEMENTS = 30;
-//1200
+const int MAX_ELEMENTS = 1200;
const int MAX_VALUE = 28000;
: application_shell()
{
}
+
DEFINE_CLASS_NAME("test_sorts")
- ;
int *populate_random_c_array(int size);
basis::array<int> populate_random_array(int size);
+ void rerandomize(int list[], int size);
+ bool verify_ascending(const int *list, int size);
+ bool verify_descending(const int *list, int size);
- void test_shell_sort(int *list, int size);
- void test_heap_sort(int *list, int size);
- void test_merge_sort(basis::array<int> &list);
+ void test_shell_sort(int size);
+ void test_heap_sort(int size);
+ void test_merge_sort(int size);
+ void test_quick_sort(int size);
virtual int execute();
};
return to_return;
}
-//hmmm: this pattern is very silly. it's nearly cookie cutter, so why not implement a templated version?
-// one diff is the C array versus basis array usage.
+void test_sorts::rerandomize(int list[], int size)
+{
+ for (int i = 0; i < size; i++)
+ list[i] = randomizer().inclusive(0, MAX_VALUE);
+}
-void test_sorts::test_shell_sort(int *list, int size)
+bool test_sorts::verify_ascending(const int *list, int size)
+{
+ FUNCDEF("verify_ascending")
+ int last = list[0];
+ for (int j = 1; j < size; j++) {
+ if (list[j] < last) return false;
+ last = list[j];
+ }
+ return true;
+}
+
+bool test_sorts::verify_descending(const int *list, int size)
+{
+ FUNCDEF("verify_descending")
+ int last = list[0];
+ for (int j = 1; j < size; j++) {
+ if (list[j] > last) return false;
+ last = list[j];
+ }
+ return true;
+}
+
+void test_sorts::test_shell_sort(int size)
{
FUNCDEF("test_shell_sort");
+ int *list = populate_random_c_array(size);
+
// check a normal sort.
shell_sort(list, size);
- int last = -1;
- for (int j = 0; j < size; j++) {
- ASSERT_FALSE(list[j] < last, "ordering check - list should be ordered at first check");
- last = list[j];
- }
+ ASSERT_TRUE(verify_ascending(list, size),
+ "ordering check - list should be ordered at first check");
- // re-randomize the list.
- for (int i = 0; i < size; i++)
- list[i] = randomizer().inclusive(0, MAX_VALUE);
+ rerandomize(list, size);
// check a reversed sort.
shell_sort(list, size, true);
- last = MAX_VALUE + 100; // past the maximum we'll include in the list.
- for (int j = 0; j < size; j++) {
- ASSERT_FALSE(list[j] > last, "ordering check - list should be ordered at second check");
- last = list[j];
- }
+ ASSERT_TRUE(verify_descending(list, size),
+ "ordering check - list should be ordered at second check");
// clean up now.
delete[] list;
}
-void test_sorts::test_heap_sort(int *list, int size)
+void test_sorts::test_heap_sort(int size)
{
FUNCDEF("test_heap_sort");
+ int *list = populate_random_c_array(size);
+
// check a normal sort.
heap_sort(list, size);
+ ASSERT_TRUE(verify_ascending(list, size),
+ "ordering check - list should be ordered at first check");
- int last = -1;
- for (int j = 0; j < size; j++) {
- ASSERT_FALSE(list[j] < last, "ordering check - list should be ordered at first check");
- last = list[j];
- }
-
- // re-randomize the list.
- for (int i = 0; i < size; i++)
- list[i] = randomizer().inclusive(0, MAX_VALUE);
+ rerandomize(list, size);
// check a reversed sort.
heap_sort(list, size, true);
-
- last = MAX_VALUE + 100; // past the maximum we'll include in the list.
- for (int j = 0; j < size; j++) {
- ASSERT_FALSE(list[j] > last, "ordering check - list should be ordered at second check");
- last = list[j];
- }
+ ASSERT_TRUE(verify_descending(list, size),
+ "ordering check - list should be ordered at second check");
// clean up now.
delete[] list;
}
-void test_sorts::test_merge_sort(basis::array<int> &list)
+void test_sorts::test_merge_sort(int size)
{
FUNCDEF("test_merge_sort");
+ basis::array<int> list = populate_random_array(size);
+
// check a normal sort.
basis::array<int> ret = merge_sort(list);
-// LOG(a_sprintf("list has %d elems", ret.length()));
// LOG(astring("list has ") + dump_list(ret.observe(), ret.length()));
- int last = -1;
- for (int j = 0; j < list.length(); j++) {
- ASSERT_FALSE(ret[j] < last, "ordering check - list should be ordered at first check");
- last = ret[j];
- }
+ ASSERT_TRUE(verify_ascending(ret.access(), size),
+ "ordering check - list should be ordered at first check");
- // re-randomize the list.
- for (int i = 0; i < list.length(); i++)
- list[i] = randomizer().inclusive(0, MAX_VALUE);
+ rerandomize(list.access(), size);
// check a reversed sort.
ret = merge_sort(list, true);
+ ASSERT_TRUE(verify_descending(ret.access(), size),
+ "ordering check - list should be ordered at second check");
+}
- last = MAX_VALUE + 100; // past the maximum we'll include in the list.
- for (int j = 0; j < list.length(); j++) {
- ASSERT_FALSE(ret[j] > last, "ordering check - list should be ordered at second check");
- last = ret[j];
- }
+void test_sorts::test_quick_sort(int size)
+{
+ FUNCDEF("test_quick_sort");
+
+ int *list = populate_random_c_array(size);
+
+ // check a normal sort.
+ quick_sort(list, size);
+ ASSERT_TRUE(verify_ascending(list, size),
+ "ordering check - list should be ordered at first check");
+
+// LOG(a_sprintf("after quick sort: %s", dump_list(list, size).s()));
+
+ rerandomize(list, size);
+
+ // check a reversed sort.
+ quick_sort(list, size, true);
+ ASSERT_TRUE(verify_descending(list, size),
+ "ordering check - list should be ordered at second check");
+
+ // clean up now.
+ delete[] list;
}
+
int test_sorts::execute()
{
FUNCDEF("execute");
int size = MAX_ELEMENTS;
- test_shell_sort(populate_random_c_array(size), size);
-
- test_heap_sort(populate_random_c_array(size), size);
+ test_shell_sort(size);
- basis::array<int> testarray = populate_random_array(size);
- test_merge_sort(testarray);
+ test_heap_sort(size);
- // test_quick_sort(populate_random_array(size), size);
+ test_merge_sort(size);
+ test_quick_sort(size);
return final_report();
}
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