public void testChangePriority() {
PriorityQueue q = new MinHeap(N);
Item items[] = new Item[N];
for (int i = 0; i < N; i++) {
Item e = new Item(N - i - 1);
q.insert(e);
items[i] = e;
}
q.changePriority(items[N - 1], -2);
q.changePriority(items[N / 2], -1);
q.changePriority(items[N / 2 + 1], N * 2);
int j = 0;
double pr_last = Double.NEGATIVE_INFINITY;
assertTrue("descending size", q.size() == N);
while (q.size() > 0) {
assertTrue("descending extract", j < N);
QueueElement e = q.extractMin();
assertTrue("descending order", e.getPriority() > pr_last);
pr_last = e.getPriority();
if (j == 0) assertTrue("lowest elt", e.getPriority() == -2);
if (j == 1) assertTrue("second-lowest elt", e.getPriority() == -1);
if (q.size() == 1) assertTrue("penultimate elt", e.getPriority() == N - 1);
if (q.size() == 0) assertTrue("final elt", e.getPriority() == N * 2);
j++;
}
}
public void testReverse() {
PriorityQueue q = new MinHeap(N);
Item items[] = new Item[N];
for (int i = 0; i < N; i++) {
Item e = new Item(N - i - 1);
q.insert(e);
items[i] = e;
}
for (int i = 0; i < N; i++) {
q.changePriority(items[i], i);
}
int j = 0;
double pr_last = Double.NEGATIVE_INFINITY;
assertTrue("ascending size", q.size() == N);
while (q.size() > 0) {
assertTrue("ascending extract", j < N);
QueueElement e = q.extractMin();
assertTrue("ascending order", e.getPriority() > pr_last);
pr_last = e.getPriority();
assertEquals("ascending priority", items[j].getPriority(), e.getPriority());
assertEquals("ascending identity", items[j], e);
j++;
}
}
public void testEqualKeys() {
PriorityQueue q = new MinHeap(N);
Item[] items = new Item[20];
int j = 0;
for (int i = 0; i < 5; i++) {
items[j] = new Item(5);
q.insert(items[j]);
j++;
}
for (int i = 0; i < 5; i++) {
items[j] = new Item(3);
q.insert(items[j]);
j++;
}
for (int i = 0; i < 5; i++) {
items[j] = new Item(4);
q.insert(items[j]);
j++;
}
for (int i = 0; i < 5; i++) {
items[j] = new Item(7);
q.insert(items[j]);
j++;
}
assertEquals(20, q.size());
for (int i = 0; i < items.length; i++) {
assertTrue(q.contains(items[i]));
}
for (int i = 0; i < 5; i++) {
QueueElement e = q.extractMin();
assertTrue(q.contains(q.min()));
assertEquals(3.0, e.getPriority());
}
for (int i = 0; i < 5; i++) {
QueueElement e = q.extractMin();
assertTrue(q.contains(q.min()));
assertEquals(4.0, e.getPriority());
}
for (int i = 0; i < 5; i++) {
QueueElement e = q.extractMin();
assertTrue(q.contains(q.min()));
assertEquals(5.0, e.getPriority());
}
for (int i = 0; i < 5; i++) {
QueueElement e = q.extractMin();
if (q.size() > 0) assertTrue(q.contains(q.min()));
assertEquals(7.0, e.getPriority());
}
}
public void testDescending() {
PriorityQueue q = new MinHeap(N);
double p[] = new double[N];
for (int i = 0; i < N; i++) {
p[i] = i;
Item e = new Item(N - i - 1);
q.insert(e);
}
int j = 0;
double pr = Double.NEGATIVE_INFINITY;
assertTrue("descending size", q.size() == N);
while (q.size() > 0) {
assertTrue("descending extract", j < N);
QueueElement e = q.extractMin();
assertTrue("descending order", e.getPriority() > pr);
assertEquals("descending priority", e.getPriority(), p[j++], 1e-5);
pr = e.getPriority();
}
}