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++; } }