LeetCode - 2.Add Two Numbers
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* addNode(ListNode* l1, ListNode* l2, int& carry) {
int sum = carry;
if (carry > 0) {
carry--;
}
if (l1) {
sum += l1->val;
}
if (l2) {
sum += l2->val;
}
if (sum > 9) {
sum = sum % 10;
carry++;
}
return new ListNode(sum);
}
ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
int carry = 0;
ListNode* head = nullptr;
ListNode* current = nullptr;
while (l1 != nullptr || l2 != nullptr || carry != 0) {
ListNode* nextNode = addNode(l1, l2, carry);
if (current) {
current->next = nextNode;
current = current->next;
} else {
head = current = nextNode;
}
if (l1) {
l1 = l1->next;
}
if (l2) {
l2 = l2->next;
}
}
return head;
}
};