2. Add Two Numbers

2. Add Two Numbers

DescriptionHintsSubmissionsDiscussSolution

 

 

DiscussPick One

---

You are given two non-empty linked lists representing two non-negative integers. 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.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
        ListNode head(0), *p = & head;
        int c = 0;
        while(l1 || l2 || c){
            int sum = (l1 ? l1 -> val: 0) + (l2 ? l2 -> val: 0) + c;
            c = sum / 10;
            p -> next = new ListNode(sum % 10);
            p = p -> next;
            l1 = l1 ? l1 -> next: l1;
            l2 = l2 ? l2 -> next: l2;
        }
        return head.next;
    }
};