1. 相交链表
https://leetcode.cn/problems/intersection-of-two-linked-lists/description/
l1=s1+s2
l2=s3+s2
s1+s2+s3长度固定
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode(int x) {
* val = x;
* next = null;
* }
* }
*/
public class Solution {
public ListNode getIntersectionNode(ListNode headA, ListNode headB) {
ListNode l1 = headA, l2 = headB;
while(l1 != l2){
l1 = (l1 == null) ? headB : l1.next;
l2 = (l2 == null) ? headA : l2.next;
}
return l1;
}
}
2. 链表反转
https://leetcode.cn/problems/reverse-linked-list/description/
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode() {}
* ListNode(int val) { this.val = val; }
* ListNode(int val, ListNode next) { this.val = val; this.next = next; }
* }
*/
class Solution {
public ListNode reverseList(ListNode head) {
ListNode prev = null;
ListNode curr = head;
while(curr != null){
ListNode next = curr.next;
curr.next = prev;
prev = curr;
curr = next;
}
return prev;
}
}