package leetcode.pr2;

import java.util.HashMap;

import java.util.Map;

public class CS {

public class ListNode {

int val;

ListNode next;

ListNode() {}

ListNode(int val) { this.val = val; }

ListNode(int val, ListNode next) { this.val = val; this.next = next; }

}

class Solution {

public ListNode addTwoNumbers(ListNode l1, ListNode l2) {

Map<Integer,Integer> map = new HashMap<>();

ListNode first = l1;

ListNode second = l2;

int keyIdx = 0;

while (first != null || second != null){

int val1 = 0;

int val2 = 0;

if (first != null){

val1 = first.val;

first = first.next;

}

if (second != null){

val2 = second.val;

second = second.next;

}

int sum = val1 + val2;

map.put(keyIdx++,sum);

}

int idx = 0;

while(idx < keyIdx){

int val = map.get(idx) ;

map.put(idx,val % 10);

int pt = idx + 1;

while(keyIdx >= pt && val >= 10){

if(keyIdx == pt){

map.put(pt,1);

break;

}

val = map.get(pt) + 1;

map.put(pt++,val % 10);

}

idx++;

}

int pt = 1;

ListNode head = new ListNode(map.get(0));

ListNode curr = head;

while (map.containsKey(pt)){

curr.next = new ListNode(map.get(pt++));

curr = curr.next;

}

return head;

}

}

}