-
Notifications
You must be signed in to change notification settings - Fork 3
/
23.cpp
37 lines (36 loc) · 1.2 KB
/
23.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
/**
* Definition for singly-linked list.
* 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) {}
* };
*/
class Solution {
public:
ListNode* mergeKLists(vector<ListNode*>& lists) {
priority_queue<pair<int, pair<int, ListNode*>>, vector<pair<int, pair<int, ListNode*>>>, greater<pair<int, pair<int, ListNode*>>>> pq;
for (int i = 0; i < lists.size(); i++) {
if (lists[i] != nullptr) {
pq.push(make_pair(lists[i]->val, make_pair(i, lists[i])));
lists[i] = lists[i]->next;
}
}
ListNode* sentinel = new ListNode();
ListNode* curr = sentinel;
while (!pq.empty()) {
auto [num, complex] = pq.top();
auto [l, node] = complex;
pq.pop();
curr->next = node;
curr = curr->next;
if (lists[l] != nullptr) {
pq.push(make_pair(lists[l]->val, make_pair(l, lists[l])));
lists[l] = lists[l]->next;
}
}
return sentinel->next;
}
};