• https://leetcode.com/problems/add-two-numbers/description/
• 2. Add Two Numbers

JavaScript 解答

var addTwoNumbers = function (l1, l2) {

    var c = 0;
    var ret = new ListNode(0);
    var curr = ret;

    while (l1 || l2) {
        var a = l1 ? l1.val : 0;
        var b = l2 ? l2.val : 0;
        var sum = a + b + c;
        c = Math.floor(sum / 10);
        curr.next = new ListNode(sum % 10);
        if (l1) {
            l1 = l1.next;
        }
        if (l2) {
            l2 = l2.next;
        }
        curr = curr.next;
    }
    if (c) {
        curr.next = new ListNode(c);
    }

    return ret.next;
};

Ruby 解答

def add_two_numbers(l1, l2)
    return add(l1,l2,0)
end

def add(l1,l2,f)
    if not l1 and not l2 and f==0
        return nil
    end
    ans=f +(l1 ? l1.val : 0)+(l2 ? l2.val : 0)
    res=ListNode.new(ans%10)
    res.next=add(l1 ? l1.next : nil,l2 ? l2.next : nil,ans/10)
    return res
end