题目

image.png

题解

题解1

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        ListNode newHead = new ListNode(-1);
        ListNode p = newHead;
        ListNode p1 = l1;
        ListNode p2 = l2;
        int sum = 0, add = 0;
        while (p1 != null && p2 != null) {
            sum = (p1.val + p2.val) % 10;
            ListNode next = new ListNode(sum + add);
            add = (p1.val + p2.val) / 10;
            p.next = next;
            p = p.next;
            p1 = p1.next;
            p2 = p2.next;
        }
        if (p1 != null) {
            ListNode next = new ListNode(p1.val + add);
            p.next = next;
            p = p.next;
            p1 = p1.next;
        }
        if (p2 != null) {
            ListNode next = new ListNode(p2.val + add);
            p.next = next;
            p = p.next;
            p2 = p2.next;
        }
        return newHead.next;
    }
}

错误

image.png

题解2

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        ListNode newHead = new ListNode(-1);
        ListNode p = newHead;
        ListNode p1 = l1;
        ListNode p2 = l2;
        int sum = 0, add = 0;
        while (p1 != null && p2 != null) {
            sum = (p1.val + p2.val + add) % 10;
            ListNode next = new ListNode(sum);
            add = (p1.val + p2.val + add) / 10;
            p.next = next;
            p = p.next;
            p1 = p1.next;
            p2 = p2.next;
        }
        while (p1 != null) {
            sum = (p1.val + add) % 10;
            ListNode next = new ListNode(sum);
            add = (p1.val + add) / 10;
            p.next = next;
            p = p.next;
            p1 = p1.next;
        }
        while (p2 != null) {
            sum = (p2.val + add) % 10;
            ListNode next = new ListNode(sum);
            add = (p2.val + add) / 10;
            p.next = next;
            p = p.next;
            p2 = p2.next;
        }
        // add
        if (add != 0) {
            ListNode next = new ListNode(add);
            p.next = next;
            p = p.next;
        }
        return newHead.next;
    }
}