LeetCode Link: https://leetcode.com/problems/add-two-numbers/
Language: C#
Problem Statement
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.
Examples
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.
Solution
/**
* Definition for singly-linked list.
* public class ListNode {
* public int val;
* public ListNode next;
* public ListNode(int val=0, ListNode next=null) {
* this.val = val;
* this.next = next;
* }
* }
*/
public class Solution {
public ListNode AddTwoNumbers(ListNode l1, ListNode l2) {
ListNode lt1 = l1;
ListNode lt2 = l2;
ListNode sum = new ListNode();
ListNode st = null;
int rem = 0;
while (lt1 != null || lt2 != null) {
if(st == null) {
st = sum;
}
else {
st.next = new ListNode();
st = st.next;
}
st.val += rem;
rem = 0;
if(lt1 != null) {
st.val += lt1.val;
lt1 = lt1.next;
}
if(lt2 != null) {
st.val += lt2.val;
lt2 = lt2.next;
}
if(st.val > 9) {
rem = 1;
st.val -= 10;
}
Console.WriteLine(st.val);
}
if(rem != 0) {
st.next = new ListNode(rem);
}
return sum;
}
}