[LeetCode] 2. Add Two Numbers (javascript)

두 Linked List를 더해주는 문제다.

리스트가 integer 크기 제한보다 길 때도 있으므로 BigInt를 사용했다.

 

/**
 * Definition for singly-linked list.
 * function ListNode(val, next) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.next = (next===undefined ? null : next)
 * }
 */
/**
 * @param {ListNode} l1
 * @param {ListNode} l2
 * @return {ListNode}
 */
var addTwoNumbers = function (l1, l2) {
    let l = '';
    let ll = '';
    while (l1) {
        l = l1.val + l;
        l1 = l1.next;
    }
    while (l2) {
        ll = l2.val + ll;
        l2 = l2.next;
    }
    const sum = BigInt(l) + BigInt(ll);
    const sumArr = sum
        .toString()
        .split('')
        .map((i) => parseInt(i));
    let result;
    for (const i in sumArr) {
        result = new ListNode(sumArr[i], result);
    }
    return result;
};

https://leetcode.com/problems/add-two-numbers/