极客大学架构师训练营 0 期 week 08 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){
       ListNode first = headA, second = headB;
        while(headA != headB){
            if(headA == null) 
                headA = second;
            else 
                headA = headA.next;
            if(headB == null) 
                headB = first;
            else
                headB = headB.next;
        }
        if(headA == null)
            return null;
        return headA; 
    }
}