add: 230312

cpp/2303/230312.cpp

@@ -0,0 +1,65 @@
+#include <queue>
+#include <vector>
+#include <iostream>
+
+struct ListNode {
+	int val;
+	ListNode* next;
+
+	explicit ListNode(int x = 0, ListNode* next = nullptr) : val(x), next(next) {}
+};
+
+ListNode* construct(int x) {
+	return new ListNode(x);
+}
+
+template<typename... Ts>
+ListNode* construct(int x, Ts... xs) {
+	return new ListNode(x, construct(xs...));
+}
+
+struct cmp {
+	bool operator()(const ListNode* x, const ListNode* y) {
+		return x && (!y || x->val > y->val);
+	}
+};
+
+/**
+ * 23. Merge k Sorted Lists
+ *
+ * You are given an array of k linked-lists lists, each linked-list is sorted in ascending order.
+ * Merge all the linked-lists into one sorted linked-list and return it.
+ */
+
+class Solution {
+public:
+	static ListNode* mergeKLists(const std::vector<ListNode*>& lists) {
+		if (lists.empty())
+			return nullptr;
+		std::priority_queue<ListNode*, std::vector<ListNode*>, cmp> q(lists.begin(), lists.end());
+		ListNode* ptr = new ListNode(0), * head = ptr;
+		for (; !q.empty() && !q.top(); q.pop());
+		while (!q.empty()) {
+			ListNode* p = q.top();
+			q.pop();
+			ptr = ptr->next = new ListNode(p->val);
+			if (p->next)
+				q.push(p->next);
+		}
+		return head->next;
+	}
+};
+
+int main() {
+	ListNode* h = Solution::mergeKLists({
+		construct(1, 4, 5),
+		nullptr,
+		construct(1, 3, 4),
+		construct(2, 6),
+		nullptr,
+		nullptr
+	});
+	for (ListNode* ptr = h; ptr; ptr = ptr->next)
+		std::cout << ptr->val << "\n";
+	return 0;
+}

cpp/2303/CMakeLists.txt

@@ -3,4 +3,4 @@ PROJECT(2303)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2303 230311.cpp)
+ADD_EXECUTABLE(2303 230312.cpp)