leetcode

Solution to some Leetcode problems written in C++
git clone git://git.dimitrijedobrota.com/leetcode.git
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0445.cpp (1074B)

      1 class Solution {
      2   public:
      3     pair<ListNode *, int> reverse(ListNode *root) {
      4         ListNode *l = nullptr, *c = root;
      5         int size = 0;
      6         while (c) {
      7             ListNode *n = c->next;
      8             c->next = l;
      9             l = c;
     10             c = n;
     11             size++;
     12         }
     13         return {l, size};
     14     }
     15 
     16     ListNode *addTwoNumbers(ListNode *p1, ListNode *p2) {
     17         auto [l1, s1] = reverse(p1);
     18         auto [l2, s2] = reverse(p2);
     19 
     20         if (s2 > s1) swap(l1, l2);
     21         p1 = l1;
     22 
     23         int carry = 0;
     24         for (; l1 && l2; l1 = l1->next, l2 = l2->next) {
     25             int sum = l1->val + l2->val + carry;
     26             l1->val = sum % 10;
     27             carry = sum / 10;
     28         }
     29 
     30         if (l1) {
     31             while (true) {
     32                 int sum = l1->val + carry;
     33                 l1->val = sum % 10;
     34                 carry = sum / 10;
     35                 if (!l1->next) break;
     36                 l1 = l1->next;
     37             }
     38         }
     39 
     40         if (!carry) return reverse(p1).first;
     41         return new ListNode(carry, reverse(p1).first);
     42     }
     43 };