2. Add Two Numbers
Đề Bài
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 contains a single digit. Add the two numbers and return the sum as a linked list.
You may assume the two numbers do not contain any leading zero, except the number 0 itself.
Example 1:
Input: l1 = [2,4,3], l2 = [5,6,4] Output: [7,0,8] Explanation: 342 + 465 = 807.
Example 2:
Input: l1 = [0], l2 = [0] Output: [0]
Example 3:
Input: l1 = [9,9,9,9,9,9,9], l2 = [9,9,9,9] Output: [8,9,9,9,0,0,0,1]
Constraints:
- The number of nodes in each linked list is in the range
[1, 100]. 0 <= Node.val <= 9- It is guaranteed that the list represents a number that does not have leading zeros.
Thuật Toán & Kỹ Thuật
⏱️ Thời gian
O(n)
💾 Không gian
O(n)
Lời Giải
C++
0002-add-two-numbers.cpp
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode() : val(0), next(nullptr) {}
* ListNode(int x) : val(x), next(nullptr) {}
* ListNode(int x, ListNode *next) : val(x), next(next) {}
* };
*/
class Solution {
public:
ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
ListNode *i = l1;
ListNode *j = l2;
ListNode *l3 = new ListNode(0);
ListNode *k = l3;
int carry = 0;
int total = 0;
while (i || j || carry) {
total = carry;
if (i) {
total += i->val;
i = i->next;
}
if (j) {
total += j->val;
j = j->next;
}
k->next = new ListNode(total % 10);
carry = total / 10;
k = k->next;
}
return l3->next;
}
};