2. Add Two Numbers
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
/** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode(int x) { val = x; } * } */ public class Solution { public ListNode addTwoNumbers(ListNode l1, ListNode l2) { ListNode pl1 = l1; ListNode pl2 = l2; ListNode head = new ListNode(0); ListNode p = head; int carry = 0; int sum; while(pl1!=null && pl2!=null){ sum = pl1.val + pl2.val + carry; carry = sum>=10?1:0; p.next = new ListNode(sum%10); p = p.next; pl1 = pl1.next; pl2 = pl2.next; } while(pl1!=null){ sum = pl1.val + carry; carry = sum>=10?1:0; p.next = new ListNode(sum%10); p = p.next; pl1 = pl1.next; } while(pl2!=null){ sum = pl2.val + carry; carry = sum>=10?1:0; p.next = new ListNode(sum%10); p = p.next; pl2 = pl2.next; } if(carry==1){ p.next = new ListNode(carry); } return head.next; } }