一位一位的相加
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode() {}
* ListNode(int val) { this.val = val; }
* ListNode(int val, ListNode next) { this.val = val; this.next = next; }
* }
*/
class Solution {
public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
ListNode result = new ListNode();
ListNode prev = result;
Boolean flag = false;
while (l1 != null || l2 != null) {
int sum = 0;
if (l1 != null) {
sum += l1.val;
l1 = l1.next;
}
if (l2 != null) {
sum += l2.val;
l2 = l2.next;
}
//进位标志
if(flag) {
sum += 1;
flag = false;
}
if(sum >= 10) {
sum = sum % 10;
flag = true;
}
prev.next = new ListNode(sum);
prev = prev.next;
}
if(flag) {
prev.next = new ListNode(1);
}
return result.next;
}
}