[算法] - leetcode 链表两数相加

public class MyTest {

    public static void main(String[] args) {
        ListNode l1 = new ListNode();
        l1.val = 5;
        ListNode l2 = new ListNode();
        l2.val = 6;
        ListNode listNode = addTwoNumbers(l1, l2);
        System.out.println(listNode);
    }

    public static ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        ListNode newListNode = new ListNode();
        ListNode curListNode = newListNode;
        int mark = 0;
        while(l1 != null || l2 != null || mark == 1){
            int a1 = 0;
            if(l1 != null){
                a1 = l1.val;
                l1 = l1.next;
            }

            int a2 = 0;
            if(l2 != null){
                a2 = l2.val;
                l2 = l2.next;
            }

            int sum = a1 + a2 + mark;
            mark = sum/10;

            curListNode.next = new ListNode();
            curListNode = curListNode.next;
            curListNode.val = sum % 10;
        }

        return newListNode.next;
    }

    static class ListNode {
        public ListNode next;
        public int val;

        @Override
        public String toString() {
            ListNode cur = this;
            String toString = "";
            while (cur != null){
                toString += (cur.val + "=>");
                cur = cur.next;
            }

            return toString += "null";
        }
    }
}

1=>1=>null