Envío 2923

Código

#include <iostream>
#include <string>

using namespace std;
struct ListNode {
    int val;
    ListNode *next;
    ListNode() : val(0), next(nullptr) {}
    ListNode(int x) : val(x), next(nullptr) {}
    ListNode(int x, ListNode *next) : val(x), next(next) {}
};


ListNode* add(ListNode* l1, ListNode* l2, int carry) {
    if (!l1 and !l2 and carry == 0) {
        return l1;
    }
    int sum = (l1 ? l1->val : 0) + (l2 ? l2->val : 0) + carry;
    carry = 0;
    if (sum > 9) {
        sum -= 10;
        carry = 1;
    }
    return new ListNode(sum, add(l1 ? l1->next : l1, l2 ? l2->next : l2, carry));
}
ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
    return add(l1, l2, 0);
}
void printList(ListNode *l1) {
    if (l1) {
        printList(l1->next);
        cout << l1->val;
    }
}
int main()
{
    string numberStr;
    cin >> numberStr;
    ListNode *number = nullptr;
    for (char c : numberStr) {
        number = new ListNode(c - '0', number);
    }
    cin >> numberStr;
    ListNode *number2 = nullptr;
    for (char c : numberStr) {
        number2 = new ListNode(c - '0', number2);
    }
    auto sol = addTwoNumbers(number, number2);
    printList(sol);
    return 0;
}