Q21 LeetCode02.07 链表相交

1.求出两链表长度

2.分情况进行长链表头结点后移

3.移至相同长度，两头结点一起后移，找到公共节点

 1 public class Solution {
 2     public ListNode getIntersectionNode(ListNode headA, ListNode headB) {
 3       
 4         ListNode curA = headA;
 5         ListNode curB = headB;
 6         int lenA = 0, lenB = 0;
 7         while (curA != null) { // 求链表A的长度
 8             lenA++;
 9             curA = curA.next;
10         }
11         while (curB != null) { // 求链表B的长度
12             lenB++;
13             curB = curB.next;
14         }
15         curA = headA;
16         curB = headB;
17         if (lenB > lenA){
18             int gap = lenB - lenA;
19              while (gap-- > 0) {
20             curB = curB.next;
21              }
22              while (curB != null) {
23             if (curA == curB) {
24                 return curB;
25             }
26             curA = curA.next;
27             curB = curB.next;
28         }
29         
30 
31         }
32 
33          if (lenB <= lenA){
34             int gap = lenA - lenB;
35             while (gap-- > 0) {
36             curA = curA.next;
37             }
38             while (curA != null) {
39             if (curA == curB) {
40                 return curA;
41             }
42             curA = curA.next;
43             curB = curB.next;
44         }
45         
46 
47             
48         }
49          return null;
50     }
51 }