Merge Two Sorted Lists LeetCode solution in C++

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class Solution {
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 public:
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  ListNode *mergeTwoLists(ListNode *l1, ListNode *l2) {
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    ListNode dummy(INT_MIN);
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    ListNode *tail = &dummy;
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    while (l1 && l2) {
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      if (l1->val < l2->val) {
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        tail->next = l1;
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        l1 = l1->next;
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      } else {
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        tail->next = l2;
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        l2 = l2->next;
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      }
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      tail = tail->next;
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    }
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    tail->next = l1 ? l1 : l2;
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    return dummy.next;
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  }
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};