package org.example;

import java.util.List;

public class AddTwoNumbers {

public ListNode addTwoNumbers(ListNode l1, ListNode l2) {

// p l1

// q l2

ListNode p = l1;

ListNode q = l2;

ListNode pre = null;

ListNode head = null;

int carry = 0;

while (p != null && q != null) {

ListNode node = new ListNode();

node.val = (p.val + q.val + carry) % 10 ;

node.next = null;

carry = (p.val + q.val + carry) / 10;

if (head == null) {

head = node;

}

if (pre != null) {

pre.next = node;

pre = node;

} else {

pre = node;

}

p = p.next;

q = q.next;

}

while (p != null) {

ListNode node = new ListNode();

node.val = (p.val + carry) % 10;

node.next = null;

carry = (p.val + carry) / 10;

if (pre != null) {

pre.next = node;

pre = node;

} else {

pre = node;

}

p = p.next;

}

while (q != null) {

ListNode node = new ListNode();

node.val = (q.val + carry) % 10;

node.next = null;

carry = (q.val + carry) / 10;

if (pre != null) {

pre.next = node;

pre = node;

} else {

pre = node;

}

q = q.next;

}

if (carry > 0) {

ListNode node = new ListNode();

node.val = carry;

node.next = null;

pre.next = node;

}

return head;

}

}