@Test
public void Test3() {
int[] nums = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
ListNode head = ListNode.constructLinkedList(nums);
ListNode actual = solution.swapPairs(head);
int[] exps = {2, 1, 4, 3, 6, 5, 8, 7, 10, 9};
ListNode expected = ListNode.constructLinkedList(exps);
assertTrue(ListNode.isSameList(actual, expected));
}
@Test
public void Test4() {
ListNode h1 = ListNode.constructLinkedList(Arrays.asList(3));
ListNode h2 = ListNode.constructLinkedList(Arrays.asList(1));
ListNode[] lists = {h1, h2};
ListNode actual = solution.mergeKLists(lists);
ListNode expected = ListNode.constructLinkedList(Arrays.asList(1, 3));
assertTrue(ListNode.isSameList(actual, expected));
}
@Test
public void Test4() {
int[] nums = {1};
ListNode head = ListNode.constructLinkedList(nums);
solution.reorderList(head);
int[] exps = {1};
ListNode expected = ListNode.constructLinkedList(exps);
assertTrue(ListNode.isSameList(head, expected));
}
@Test
public void Test3() {
int[] nums = {1, 2, 3, 4, 5, 6, 7, 8, 9};
ListNode head = ListNode.constructLinkedList(nums);
solution.reorderList(head);
int[] exps = {1, 9, 2, 8, 3, 7, 4, 6, 5};
ListNode expected = ListNode.constructLinkedList(exps);
assertTrue(ListNode.isSameList(head, expected));
}
// 1 -> 3-> 5 \
// ==> 1->2->3->4->5
// 2 -> 4 /
@Test
public void Test4() {
int[] nums1 = {1, 3, 5};
ListNode l1 = ListNode.constructLinkedList(nums1);
int[] nums2 = {2, 4};
ListNode l2 = ListNode.constructLinkedList(nums2);
ListNode actual = solution.mergeTwoLists(l1, l2);
int[] exps = {1, 2, 3, 4, 5};
ListNode expected = ListNode.constructLinkedList(exps);
assertTrue(ListNode.isSameList(actual, expected));
}
@Test
public void Test1() {
ListNode node11 = new ListNode(1);
ListNode node21 = new ListNode(2);
ListNode actual = solution.mergeTwoLists(node11, node21);
ListNode node1 = new ListNode(1);
ListNode node2 = new ListNode(2);
node1.next = node2;
ListNode expect = node1;
assertTrue(ListNode.isSameList(actual, expect));
}
@Test
public void Test0() {
ListNode node11 = null;
ListNode node21 = null;
ListNode actual = solution.mergeTwoLists(node11, node21);
ListNode expect = null;
assertTrue(ListNode.isSameList(actual, expect));
}
public ListNode deleteDuplicates(ListNode head) {
ListNode dummy = new ListNode(0);
dummy.next = head;
ListNode pre = dummy; // last unique node we found
ListNode node = pre.next;
while (node != null) {
// find the last node that has the same value as current node
while (node.next != null && node.next.val == node.val) {
node = node.next;
}
// now, node has different value from its next node (if next
// node exists), we need to compare with previous node to
// see whether `node` has unique value
if (pre.next == node) {
// ! don't use (pre.val == node.val) unless you are sure
// dummy has different value from head node
pre = node;
} else {
pre.next = node.next;
}
node = node.next;
}
return dummy.next;
}