diff --git a/cpp/merge-in-between-linked-lists.cpp b/cpp/merge-in-between-linked-lists.cpp new file mode 100644 index 0000000..17d6c5b --- /dev/null +++ b/cpp/merge-in-between-linked-lists.cpp @@ -0,0 +1,34 @@ +#ifdef _MF_TEST +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) {} +}; +#endif + +class Solution { + public: + ListNode *mergeInBetween(ListNode *list1, int a, int b, ListNode *list2) { + auto left = list1; + for (int i = 1; i < a; ++i) { + left = left->next; + } + + auto right = left; + for (int i = a; i < b + 2; ++i) { + right = right->next; + } + + left->next = list2; + + auto last_mid = list2; + while (last_mid->next != nullptr) { + last_mid = last_mid->next; + } + last_mid->next = right; + + return list1; + } +};