You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.
Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
题目比较简单, 主要考察链表操作的熟练程度, 以及各种边界情况的处理, 这种题目, 要一次写对, 不留 bug.
1 public ListNode addTwoNumbers(ListNode l1, ListNode l2) { 2 if (l1 == null) return l2; 3 if (l2 == null) return l1; 4 5 ListNode head = new ListNode(0); 6 ListNode curr = head; 7 boolean isCarry = false; 8 while (l1 != null || l2 != null) { 9 int val = (isCarry ? 1 : 0) + (l1 == null ? 0 : l1.val) + (l2 == null ? 0 : l2.val); 10 if (val >= 10) { 11 isCarry = true; 12 val -= 10; 13 } else { 14 isCarry = false; 15 } 16 ListNode node = new ListNode(val); 17 curr.next = node; 18 curr = node; 19 l1 = l1 == null ? null : l1.next; 20 l2 = l2 == null ? null : l2.next; 21 } 22 23 if (isCarry) { 24 ListNode node = new ListNode(1); 25 curr.next = node; 26 } 27 28 return head.next; 29 }
Interview - Add two number - #2
原文：http://www.cnblogs.com/dbalgorithm/p/5169232.html