第八周作业

/**

* 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) {

if(headA == null || headB == null) return null;

ListNode pointA = headA;

ListNode pointB = headB;

while(pointA == null || pointB == null || pointA.val != pointB.val) {

if(pointA == null) {

pointA = headB;

} else {

pointA = pointA.next;

}

if(pointB == null) {

pointB = headA;

} else {

pointB = pointB.next;

}

}

return pointA;

}

}

双指针法

时间复杂度 O(m+n)

空间复杂度 O(1)