1. JZ6 从尾到头打印链表
输入：
{1,2,3}
返回值：
[3,2,1]
public ArrayList<Integer> printListFromTailToHead(ListNode listNode) { //用来存储链表中节点的值。 Stack<Integer> reverse = new Stack<>(); while(listNode != null){ reverse.push(listNode.val); listNode = listNode.next; } //创建的题目要求的数据类型来存储反向的节点值。 ArrayList<Integer> result = new ArrayList<>(); while(!reverse.isEmpty()){ //将值从栈中弹出，并添加到ArrayList中 result.add(reverse.pop()); } return result; }
2. 反转链表
public ListNode ReverseList(ListNode head) { if (head == null || head.next == null) return head; ListNode node = ReverseList(head.next); head.next.next = head; head.next = null; return node; }
3. 合并两个有序链表
public ListNode Merge(ListNode list1,ListNode list2) { if(list1==null) return list2; if(list2==null) return list1; if(list1.val<list2.val){ list1.next = Merge(list1.next,list2); return list1; } else { list2.next = Merge(list1,list2.next); return list2; } }
4 两个链表第一个公共节点
public ListNode FindFirstCommonNode(ListNode pHead1, ListNode pHead2) { ListNode l1 = pHead1, l2 = pHead2; while(l1 != l2){ l1 = (l1==null)?pHead2:l1.next; l2 = (l2==null)?pHead1:l2.next; } return l1; }
5. 删除链表的某个节点
public ListNode deleteNode (ListNode head, int val) { while(head != null && head.val == val){ head = head.next; } ListNode prev = head; if(prev!=null){ while(prev.next!=null){ if(prev.next.val == val){ prev.next = prev.next.next; }else{ prev = prev.next; } } } return head; }
6 删除链表重复节点
public ListNode deleteDuplication(ListNode head) { if(head == null || head.next == null){ return head; } //两个循环，用来应付“1-1-2-2-3-3-4-5…”格式的连续重复结点 while(head != null && head.next != null && head.val == head.next.val){ while(head != null && head.next != null && head.val == head.next.val){ head = head.next; } head = head.next; } if(head!=null ){ head.next = deleteDuplication(head.next); } return head; }
