002.Add Two Numbers

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
public class Solution {
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        int len1 = 0, len2 = 0;
        ListNode temp1 = l1,temp2 = l2;
        while(temp1 != null){
            len1++;
            temp1 = temp1.next;
        }
            
        while(temp2 != null){
            len2++;
            temp2 = temp2.next;
        }
        
        int len = len1 > len2 ? len1 : len2;
        int[] num1 = new int[len];
        int[] num2 = new int[len];
        int[] numRes = new int[len+1];
        int index1 = 0, index2 = 0;
        
        temp1 = l1;
        temp2 = l2;
        while(temp1 != null){
            num1[index1++] = temp1.val;
            temp1 = temp1.next;
        }
        
        while(temp2 != null){
            num2[index2++] = temp2.val;
            temp2 = temp2.next;
        }
        
        for(int i = 0; i < len; i++){
            numRes[i] += num1[i] + num2[i];
            numRes[i+1] += numRes[i] / 10;
            numRes[i] %= 10;
        }
        
        ListNode res = new ListNode(numRes[0]);
        ListNode p = res;
        int end = 1;
        if(numRes[len] != 0){
            len++;
        }
        while(end < len){
            ListNode t = new ListNode(numRes[end]);
            p.next = t;
            p = t;
            end++;
        }
        return res;
    }
}