Implement min heap

tests/CMakeLists.txt

@@ -20,5 +20,6 @@ add_test_suites(
   construct_tests.c
   desugar_tests.c
   fsa_tests.c
+  min_heap_tests.c
   parse_tests.c
 )

tests/min_heap_tests.c

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) Camden Dixie O'Brien
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+#include "min_heap.h"
+#include "testing.h"
+
+#include <stdbool.h>
+
+static bool is_min_heap(int *xs, int count)
+{
+	for (int i = 0; i < count; ++i) {
+		const int left = 2 * i + 1;
+		const int right = 2 * i + 2;
+		if (left < count && xs[left] < xs[i])
+			return false;
+		if (right < count && xs[right] < xs[i])
+			return false;
+	}
+	return true;
+}
+
+static void array_is_min_heap_after_heapify(void)
+{
+	int xs[] = { 54, 12, 35, 43, 21, 12, 34, 52, 34, 23 };
+	const int len = sizeof(xs) / sizeof(int);
+	min_heap_heapify(xs, len);
+	ASSERT_TRUE(is_min_heap(xs, len));
+}
+
+static void extract_root_yields_min(void)
+{
+	int xs[] = { 71, 31, 12, 21, 65, 53, 54, 10 };
+	int len = 8;
+	min_heap_heapify(xs, len);
+	ASSERT_EQ(10, min_heap_pop(xs, &len));
+	ASSERT_EQ(12, min_heap_pop(xs, &len));
+	ASSERT_EQ(21, min_heap_pop(xs, &len));
+	ASSERT_EQ(5, len);
+}
+
+int main(void)
+{
+	TESTING_BEGIN();
+	array_is_min_heap_after_heapify();
+	extract_root_yields_min();
+	return TESTING_END();
+}