架构师训练营—第八周作业

public class Node {
  public int val;
  public Node next;
}

public class Solution {
    public Node intersectionPointOfTwoLinkedList(Node list1, Node list2) {
        int length1 = length(list1), length2 = length(list2);
        Node headLong = null, headShort = null;
        if (length1 - length2 > 0) {
            headLong = list1;
            headShort = list2;
        } else {
            headLong = list2;
            headShort = list1;
        }
        int diff = Math.abs(length1 - length2);
        for (int i = 0; i < diff; i++) {
            headLong = headLong.next;
        }
        while (headLong != null && headShort != null && headLong != headShort) {
            headLong = headLong.next;
            headShort = headShort.next;
        }
        return headLong;
    }
    private int length(Node list) {
        int length = 0;
        if (list != null) {
            Node p = list;
            while (p != null) {
                length++;
                p = p.next;
            }
        }
        return length;
    }
}