Function add

javascript/0002-add-two-numbers.js:19–30

(l1, l2, tail, sentinel, carry = 0)

};

const add = (l1, l2, tail, sentinel, carry = 0) => {
    const isBaseCase = !(l1 || l2 || carry);
    if (isBaseCase) return sentinel.next;

    return dfs(
        l1,
        l2,
        tail,
        sentinel,
        carry,
    ); /* Time O(MAX(N, M)) | Space O(MAX(N, M)) */
};

const dfs = (l1, l2, tail, sentinel, carry) => {
    const sum = (l1?.val || 0) + (l2?.val || 0) + carry;