56 lines
1.2 KiB
C++
56 lines
1.2 KiB
C++
#include <cstdio>
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/**
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* Definition for singly-linked list.
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*/
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struct ListNode {
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int val;
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ListNode* next;
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explicit ListNode(int x = 0, ListNode* next = nullptr) : val(x), next(next) {}
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};
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/**
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* 21. Merge Two Sorted Lists
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* You are given the heads of two sorted linked lists list1 and list2.
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* Merge the two lists in a one sorted list. The list should be made by splicing together the nodes of the first two lists.
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* Return the head of the merged linked list.
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*/
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class Solution {
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public:
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static ListNode* mergeTwoLists(ListNode* list1, ListNode* list2) {
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ListNode node;
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ListNode* ptr = &node;
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while (list1 && list2) {
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if (list1->val < list2->val) {
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list1 = (ptr->next = list1)->next;
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} else {
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list2 = (ptr->next = list2) ->next;
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}
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ptr = ptr->next;
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}
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ptr->next = list1 ? list1 : list2;
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return node.next;
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}
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};
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ListNode* construct(int x) {
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return new ListNode(x);
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}
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template<typename... Ts>
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ListNode* construct(int x, Ts... xs) {
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return new ListNode(x, construct(xs...));
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}
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int main() {
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ListNode* list1 = construct(1, 2, 4);
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ListNode* list2 = construct(1, 3, 4);
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ListNode* head = Solution::mergeTwoLists(list1, list2);
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for (ListNode* ptr = head; ptr; ptr = ptr->next) {
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std::printf("%d ", ptr->val);
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}
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return 0;
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}
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