数据结构与算法 - 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 currentHeadA = headA;
        ListNode currentHeadB = headB;
        int count = 0;
        while(currentHeadA != currentHeadB)
        {
            if (currentHeadA.next == null ) {
                currentHeadA = headB;
                count++;
            } else {
                currentHeadA = currentHeadA.next;
            }
            currentHeadB = currentHeadB.next != null ? currentHeadB.next : headA;
            if (count > 1) {
                return null;
            }
        } 
        return currentHeadA;
    }
}