# C# 中的優先佇列

Minahil Noor 2023年10月12日

## 在 C# 中使用列表作為優先佇列

``````PUSH(HEAD, VALUE, PRIORITY)
Step 1 : Create a new node with VALUE and PRIORITY Step 2
: Check if HEAD has lower priority.If true follow Steps 3 -
4 and end.Else goto Step 5. Step 3 : NEW->NEXT = HEAD Step 4 : HEAD = NEW Step 5
: Set TEMP to head of the list Step 6
: While TEMP->NEXT != NULL and TEMP->NEXT->PRIORITY > PRIORITY Step 7
: TEMP = TEMP->NEXT[END OF LOOP] Step 8 : NEW->NEXT = TEMP->NEXT Step 9
: TEMP->NEXT = NEW Step 10 : End POP(HEAD) Step 2
: Set the head of the list to the next node in the list.HEAD = HEAD->NEXT.Step 3
: Free the node at the head of the list Step 4 : End TOP(HEAD)
: Step 1 : Return HEAD->VALUE Step 2 : End
``````

`push` 操作會將元素新增到優先佇列，以使優先順序最高的元素始終位於最前面。彈出操作將從佇列中刪除具有最高優先順序的元素。最上面的操作將檢索最高優先順序的元素，而不會將其刪除。下面的程式顯示瞭如何從優先佇列中推送，彈出和放置頂部元素。

``````using System;

class PriorityQueue {
public class Node {
public int data;
public int priority;
public Node next;
}

public static Node node = new Node();

public static Node newNode(int d, int p) {
Node temp = new Node();
temp.data = d;
temp.priority = p;
temp.next = null;
return temp;
}

public static int top(Node head) {
}

public static Node pop(Node head) {
Node temp = head;
}

public static Node push(Node head, int d, int p) {
Node start = (head);
Node temp = newNode(d, p);
if ((head).priority > p) {
} else {
while (start.next != null && start.next.priority < p) {
start = start.next;
}
temp.next = start.next;
start.next = temp;
}
}
public static int isEmpty(Node head) {
return ((head) == null) ? 1 : 0;
}
public static void Main(string[] args) {
Node queue = newNode(1, 1);
queue = push(queue, 9, 2);
queue = push(queue, 7, 3);
queue = push(queue, 3, 0);

while (isEmpty(queue) == 0) {
Console.Write("{0:D} ", top(queue));
queue = pop(queue);
}
}
}
``````

``````3 1 9 7
``````

`priority` 值較小的元素具有較高優先順序。