力扣HOT100 - 160. 相交链表

解题思路：

/**
 * 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 pa = headA;
        ListNode pb = headB;
        while (pa != pb) {
            pa = (pa != null) ? pa.next : headB;
            pb = (pb != null) ? pb.next : headA;
            if (pa == null && pb == null) return null;
        }
        return pa;
    }
}