题解 | #链表相加(二)#

using System;
using System.Collections.Generic;

/*
public class ListNode
{
    public int val;
    public ListNode next;

    public ListNode (int x)
    {
        val = x;
    }
}
*/

class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param head1 ListNode类
     * @param head2 ListNode类
     * @return ListNode类
     */
    public ListNode addInList (ListNode head1, ListNode head2) {

        ListNode l1 = ReverseList(head1);
        ListNode l2 = ReverseList(head2);
        ListNode l3 = new ListNode(0);
        ListNode p3 = l3;
        int curx = 0;
        while(l1 != null || l2 != null){
            if(l1 != null){
                curx += l1.val;
                l1 = l1.next;
            }
            if(l2 != null){
                curx += l2.val;
                l2 = l2.next;
            }
            p3.next = new ListNode(curx % 10);
            curx = curx / 10;
            p3 = p3.next;
        }
        if(curx != 0) p3.next = new ListNode(curx % 10);
        return ReverseList(l3.next);
    }

    public ListNode ReverseList(ListNode head) {
        ListNode slow = null;
        ListNode fast = head;
        ListNode nex;
        while(fast != null){
            nex = fast.next;
            fast.next = slow;
            slow = fast;
            fast = nex;
        }
        return slow;
    }
}