Problem,
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]
Solution,
Reverse Order λΌκΈΈλ λ©μ²νκ² μ²μμλ Stack μΌλ‘ μ§°λ€ (..). 무μ²μ΄λ κ°λ°μ μ€λ½κ²λ 0
λ² μΈλ±μ€λ₯Ό κ³ λ €ν κ²μ΄μλ€. μ λ° μ΄λ° λ©μ²ν μ€μλ νμ§ λ§μ.
μ°κ²° 리μ€νΈλ₯Ό λκΉμ§ νμνλ©° λνλ©΄ λ.
import java.util.*;
class Solution {
public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
ListNode p1 = l1;
ListNode p2 = l2;
ListNode result = new ListNode(-1);
ListNode ret = result;
int carry = 0;
while (p1 != null || p2 != null) {
int val = (p1 != null ? p1.val : 0) + (p2 != null ? p2.val : 0) + carry;
result.next = new ListNode(val % 10);
result = result.next;
carry = val / 10;
if (p1 != null) p1 = p1.next;
if (p2 != null) p2 = p2.next;
}
if (carry != 0) result.next = new ListNode(1);
return ret.next;
}
}