Linked List Operations

A linked list stores values in nodes that point to the next node, so adding or removing at the front is cheap. Simulate one that starts empty.

Process the operations in order:

• push_front x: add x at the front.
• push_back x: add x at the back.
• pop_front: remove the first value (ignored when the list is empty).
• remove x: remove the first node whose value is x, if there is one.
• reverse: reverse the order of the nodes.

Implement linked_list_operations(operations).

Input

operations: The operations.

Output

Return the values in the list from front to back.

เงื่อนไข

0 ≤ number of operations ≤ 10,000

−10^9 ≤ x ≤ 10^9

ตัวอย่าง

อินพุต:
operations = ["push_back 2", "push_front 1", "push_back 3", "reverse"]

ผลลัพธ์ที่คาดหวัง:
expected = [3, 2, 1]

อินพุต:
std::vector<std::string> operations = {"push_back 2", "push_front 1", "push_back 3", "reverse"};

ผลลัพธ์ที่คาดหวัง:
std::vector<long long> expected = {3, 2, 1};

อินพุต:
string[] operations = new string[] {"push_back 2", "push_front 1", "push_back 3", "reverse"};

ผลลัพธ์ที่คาดหวัง:
long[] expected = new long[] {3, 2, 1};

อินพุต:
operations = ["push_back 5", "push_back 7", "push_back 5", "remove 5", "pop_front"]

ผลลัพธ์ที่คาดหวัง:
expected = [5]

อินพุต:
std::vector<std::string> operations = {"push_back 5", "push_back 7", "push_back 5", "remove 5", "pop_front"};

ผลลัพธ์ที่คาดหวัง:
std::vector<long long> expected = {5};

อินพุต:
string[] operations = new string[] {"push_back 5", "push_back 7", "push_back 5", "remove 5", "pop_front"};

ผลลัพธ์ที่คาดหวัง:
long[] expected = new long[] {5};

แหล่งอ้างอิง

โจทย์นี้ปรับให้เหมาะกับ CodeUtility กรุณาทำตามคำชี้แจงและข้อจำกัดด้านบน

• cppreference, std::list