以下代码不适用于以下输入:[2,4,3][5,6,4]输出:[7,8]预期的:[7,0,8]
The following code is not working for the below Input: [2,4,3] [5,6,4] Output: [7,8] Expected: [7,0,8]
为什么我没有得到0?谁能帮我.
Why I am not getting 0? Can anyone please help me.
/** * Definition for singly-linked list. * public class ListNode { * public int val; * public ListNode next; * public ListNode(int x) { val = x; } * } */ public class Solution { public ListNode AddTwoNumbers(ListNode l1, ListNode l2) { return AddTwoNumbersHelper(l1, l2, 0); } private ListNode AddTwoNumbersHelper(ListNode l1, ListNode l2, int carry) { if (l1 == null && l2 == null) return null; int temp = 0; if (l1 != null) temp += l1.val; if (l2 != null) temp += l2.val; ListNode result = new ListNode(temp % 10); carry = temp / 10; l1 = l1.next; l2 = l2.next; int sum = 0; while(l1 != null || l2 != null) { sum = carry; if (l1 != null) sum += l1.val; if (l2 != null) sum += l2.val; carry = sum == 0 ? 0 : sum / 10; sum = sum % 10; result.next = new ListNode(sum); if(l1 != null) l1 = l1.next; if(l2 != null) l2 = l2.next; } if (carry > 0) result.next = new ListNode(carry); return result; }}
推荐答案代码存在一些缺陷:
这是经过稍微修改的解决方案，可以解决上述问题:
Here's a slightly modified solution which fixes the above problems:
private ListNode AddTwoNumbersHelper(ListNode l1, ListNode l2) { ListNode result = null; ListNode tail = null; int carry = 0; while ((l1 != null) || (l2 != null) || (carry != 0)) { int sum = carry; if (l1 != null) { sum += l1.val; l1 = l1.next; } if (l2 != null) { sum += l2.val; l2 = l2.next; } carry = sum/10; sum %= 10; if (result == null) { // first time result = new ListNode(sum); tail = result; } else { tail.next = new ListNode(sum); tail = tail.next; } } return result; }