37 lines
1.3 KiB
C++
37 lines
1.3 KiB
C++
/**
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* Definition for singly-linked list.
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* struct ListNode {
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* int val;
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* ListNode *next;
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* ListNode() : val(0), next(nullptr) {}
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* ListNode(int x) : val(x), next(nullptr) {}
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* ListNode(int x, ListNode *next) : val(x), next(next) {}
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* };
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*/
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class Solution {
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public:
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ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
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ListNode dummy(0); // Dummy node to simplify result list creation
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ListNode* p = &dummy; // Pointer to build the new list
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int carry = 0; // To track the carry from additions
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while (l1 != nullptr || l2 != nullptr || carry) {
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int sum = carry;
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if (l1 != nullptr) {
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sum += l1->val; // Add value from l1 if not reached its end
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l1 = l1->next; // Move to the next node in l1
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}
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if (l2 != nullptr) {
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sum += l2->val; // Add value from l2 if not reached its end
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l2 = l2->next; // Move to the next node in l2
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}
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carry = sum / 10; // Calculate the carry
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p->next = new ListNode(sum % 10); // Create a new node with the digit value
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p = p->next; // Move pointer to the newly created node
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}
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return dummy.next; // Return the result linked list
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}
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}; |