题解 | #链表相加(二)#

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 *   public ListNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public 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) {
        if (head1 == null) {
            return head2;
        }
        if (head2 == null) {
            return head1;
        }
        int length1 = 0;
        List num1 = new ArrayList();
        int length2 = 0;
        List num2 = new ArrayList();
        ListNode temp1 = head1;
        ListNode temp2 = head2;
        while (temp1 != null) {
            length1++;
            num1.add(temp1);
            temp1 = temp1.next;
        }
        while (temp2 != null) {
            length2++;
            num2.add(temp2);
            temp2 = temp2.next;
        }
        List dataTemp;
        List otherTemp;
        int sub;
        ListNode result = null;
        ListNode resultNext;
        List resultData = new ArrayList();
        int tempNum = 0;
        if (length1 > length2) {
            dataTemp = num1;
            otherTemp = num2;
            sub = length1 - length2;
        } else {
            dataTemp = num2;
            otherTemp = num1;
            sub = length2 - length1;
        }
        for (int i = dataTemp.size() - 1; i >= 0; i--) {
            int j = i - sub;
            int minData = 0;
            if (j <= otherTemp.size() && j >= 0) {
                ListNode aaa = (ListNode) otherTemp.get(j);
                minData = aaa.val;
            }
            ListNode xxx = (ListNode) dataTemp.get(i);
            int countNum = minData + xxx.val + tempNum;
            if (countNum > 9) {
                tempNum = 1;
            } else {
                tempNum = 0;
            }
            resultData.add(countNum % 10);
        }
        if (tempNum > 0) {
            resultData.add(tempNum);
        }
        ListNode tempData = null;
        for (int i = resultData.size() - 1; i >= 0; i--) {
            if (i == resultData.size() - 1) {
                result = new ListNode((Integer) resultData.get(i));
                tempData = result;
            } else {
                ListNode temp = new ListNode((Integer) resultData.get(i));
                tempData.next = temp;
                tempData = temp;

            }
        }
        return result;
    }
}