📌  相关文章
📜  将仲裁指针指向链表中的最大值右侧节点

📅  最后修改于: 2022-05-13 01:57:45.461000             🧑  作者: Mango

将仲裁指针指向链表中的最大值右侧节点

给定单链表,每个节点都有一个额外的“任意”指针,当前指向 NULL。我们需要将“任意”指针指向链表右侧的最大值节点。

listwithArbit1

一个简单的解决方案是一个一个地遍历所有节点。对于每个节点,在右侧找到具有最大值的节点并更改下一个指针。此解决方案的时间复杂度为 O(n 2 )。

一个有效的解决方案可以在 O(n) 时间内工作。下面是步骤。



  1. 反转给定的链表。
  2. 开始遍历链表并存储到目前为止遇到的最大值节点。使每个节点的仲裁指向最大值。如果当前节点中的数据多于目前的max节点,则更新max。
  3. 反向修改链表并返回头部。

下面是上述步骤的实现。

C++
// C++ program to point arbit pointers to highest
// value on its right
#include
using namespace std;
 
/* Link list node */
struct Node
{
    int data;
    Node* next, *arbit;
};
 
/* Function to reverse the linked list */
Node* reverse(Node *head)
{
    Node *prev = NULL, *current = head, *next;
    while (current != NULL)
    {
        next  = current->next;
        current->next = prev;
        prev = current;
        current = next;
    }
    return prev;
}
 
// This function populates arbit pointer in every
// node to the greatest value to its right.
Node* populateArbit(Node *head)
{
    // Reverse given linked list
    head = reverse(head);
 
    // Initialize pointer to maximum value node
    Node *max = head;
 
    // Traverse the reversed list
    Node *temp = head->next;
    while (temp != NULL)
    {
        // Connect max through arbit pointer
        temp->arbit = max;
 
        // Update max if required
        if (max->data < temp->data)
            max = temp;
 
        // Move ahead in reversed list
        temp = temp->next;
    }
 
    // Reverse modified linked list and return
    // head.
    return reverse(head);
}
 
// Utility function to print result linked list
void printNextArbitPointers(Node *node)
{
    printf("Node\tNext Pointer\tArbit Pointer\n");
    while (node!=NULL)
    {
        cout << node->data << "\t\t";
 
        if (node->next)
            cout << node->next->data << "\t\t";
        else cout << "NULL" << "\t\t";
 
        if (node->arbit)
            cout << node->arbit->data;
        else cout << "NULL";
 
        cout << endl;
        node = node->next;
    }
}
 
/* Function to create a new node with given data */
Node *newNode(int data)
{
    Node *new_node = new Node;
    new_node->data = data;
    new_node->next = NULL;
    return new_node;
}
 
/* Driver program to test above functions*/
int main()
{
    Node *head = newNode(5);
    head->next = newNode(10);
    head->next->next = newNode(2);
    head->next->next->next = newNode(3);
 
    head = populateArbit(head);
 
    printf("Resultant Linked List is: \n");
    printNextArbitPointers(head);
 
    return 0;
}


Java
// Java program to point arbit pointers to highest
// value on its right
class GfG
{
 
/* Link list node */
static class Node
{
    int data;
    Node next, arbit;
}
 
/* Function to reverse the linked list */
static Node reverse(Node head)
{
    Node prev = null, current = head, next = null;
    while (current != null)
    {
        next = current.next;
        current.next = prev;
        prev = current;
        current = next;
    }
    return prev;
}
 
// This function populates arbit pointer in every
// node to the greatest value to its right.
static Node populateArbit(Node head)
{
    // Reverse given linked list
    head = reverse(head);
 
    // Initialize pointer to maximum value node
    Node max = head;
 
    // Traverse the reversed list
    Node temp = head.next;
    while (temp != null)
    {
        // Connect max through arbit pointer
        temp.arbit = max;
 
        // Update max if required
        if (max.data < temp.data)
            max = temp;
 
        // Move ahead in reversed list
        temp = temp.next;
    }
 
    // Reverse modified linked list and return
    // head.
    return reverse(head);
}
 
// Utility function to print result linked list
static void printNextArbitPointers(Node node)
{
    System.out.println("Node\tNext Pointer\tArbit Pointer");
    while (node != null)
    {
        System.out.print(node.data + "\t\t");
 
        if (node.next != null)
            System.out.print(node.next.data + "\t\t");
        else
            System.out.print("NULL" +"\t\t");
 
        if (node.arbit != null)
            System.out.print(node.arbit.data);
        else
            System.out.print("NULL");
 
        System.out.println();
        node = node.next;
    }
}
 
/* Function to create a new node with given data */
static Node newNode(int data)
{
    Node new_node = new Node();
    new_node.data = data;
    new_node.next = null;
    return new_node;
}
 
/* Driver code*/
public static void main(String[] args)
{
    Node head = newNode(5);
    head.next = newNode(10);
    head.next.next = newNode(2);
    head.next.next.next = newNode(3);
 
    head = populateArbit(head);
 
    System.out.println("Resultant Linked List is: ");
    printNextArbitPointers(head);
 
}
}
 
// This code is contributed by Prerna Saini.


Python
# Python Program to point arbit pointers to highest
# value on its right
 
# Node class
class Node:
 
    # Constructor to initialize the node object
    def __init__(self, data):
        self.data = data
        self.next = None
        self.arbit = None
 
# Function to reverse the linked list
def reverse(head):
 
    prev = None
    current = head
    next = None
    while (current != None):
     
        next = current.next
        current.next = prev
        prev = current
        current = next
     
    return prev
 
# This function populates arbit pointer in every
# node to the greatest value to its right.
def populateArbit(head):
 
    # Reverse given linked list
    head = reverse(head)
 
    # Initialize pointer to maximum value node
    max = head
 
    # Traverse the reversed list
    temp = head.next
    while (temp != None):
     
        # Connect max through arbit pointer
        temp.arbit = max
 
        # Update max if required
        if (max.data < temp.data):
            max = temp
 
        # Move ahead in reversed list
        temp = temp.next
     
    # Reverse modified linked list and return
    # head.
    return reverse(head)
 
# Utility function to print result linked list
def printNextArbitPointers(node):
 
    print("Node\tNext Pointer\tArbit Pointer\n")
    while (node != None):
     
        print( node.data , "\t\t",end = "")
 
        if (node.next != None):
            print( node.next.data , "\t\t",end = "")
        else :
            print( "None" , "\t\t",end = "")
 
        if (node.arbit != None):
            print( node.arbit.data,end = "")
        else :
            print( "None",end = "")
         
        print("\n")
        node = node.next
     
# Function to create a new node with given data
def newNode(data):
 
    new_node = Node(0)
    new_node.data = data
    new_node.next = None
    return new_node
 
# Driver code
 
head = newNode(5)
head.next = newNode(10)
head.next.next = newNode(2)
head.next.next.next = newNode(3)
 
head = populateArbit(head)
 
print("Resultant Linked List is: \n")
printNextArbitPointers(head)
 
# This code is contributed by Arnab Kundu


C#
// C# program to point arbit pointers 
// to highest value on its right
using System;
 
class GfG
{
 
    /* Link list node */
    class Node
    {
        public int data;
        public Node next, arbit;
    }
 
    /* Function to reverse the linked list */
    static Node reverse(Node head)
    {
        Node prev = null, current = head, next = null;
        while (current != null)
        {
            next = current.next;
            current.next = prev;
            prev = current;
            current = next;
        }
        return prev;
    }
 
    // This function populates arbit pointer in every
    // node to the greatest value to its right.
    static Node populateArbit(Node head)
    {
        // Reverse given linked list
        head = reverse(head);
 
        // Initialize pointer to maximum value node
        Node max = head;
 
        // Traverse the reversed list
        Node temp = head.next;
        while (temp != null)
        {
            // Connect max through arbit pointer
            temp.arbit = max;
 
            // Update max if required
            if (max.data < temp.data)
                max = temp;
 
            // Move ahead in reversed list
            temp = temp.next;
        }
 
        // Reverse modified linked list 
        // and return head.
        return reverse(head);
    }
 
    // Utility function to print result linked list
    static void printNextArbitPointers(Node node)
    {
        Console.WriteLine("Node\tNext Pointer\tArbit Pointer");
        while (node != null)
        {
            Console.Write(node.data + "\t\t");
 
            if (node.next != null)
                Console.Write(node.next.data + "\t\t");
            else
                Console.Write("NULL" +"\t\t");
 
            if (node.arbit != null)
                Console.Write(node.arbit.data);
            else
                Console.Write("NULL");
 
            Console.WriteLine();
            node = node.next;
        }
    }
 
    /* Function to create a new node with given data */
    static Node newNode(int data)
    {
        Node new_node = new Node();
        new_node.data = data;
        new_node.next = null;
        return new_node;
    }
 
    /* Driver code*/
    public static void Main(String[] args)
    {
        Node head = newNode(5);
        head.next = newNode(10);
        head.next.next = newNode(2);
        head.next.next.next = newNode(3);
 
        head = populateArbit(head);
 
        Console.WriteLine("Resultant Linked List is: ");
        printNextArbitPointers(head);
    }
}
 
/* This code is contributed by 29AjayKumar */


Javascript


C++
// C++ program to point arbit pointers to highest
// value on its right
#include
using namespace std;
 
/* Link list node */
struct Node
{
    int data;
    Node* next, *arbit;
};
 
// This function populates arbit pointer in every
// node to the greatest value to its right.
void populateArbit(Node *head)
{
    // using static maxNode to keep track of maximum
    // orbit node address on right side
    static Node *maxNode;
 
    // if head is null simply return the list
    if (head == NULL)
        return;
 
    /* if head->next is null it means we reached at
       the last node just update the max and maxNode */
    if (head->next == NULL)
    {
        maxNode = head;
        return;
    }
 
    /* Calling the populateArbit to the next node */
    populateArbit(head->next);
 
    /* updating the arbit node of the current
     node with the maximum value on the right side */
    head->arbit = maxNode;
 
    /* if current Node value id greater then
     the previous right node then  update it */
    if (head->data > maxNode->data)
        maxNode = head;
 
   return;
}
 
// Utility function to print result linked list
void printNextArbitPointers(Node *node)
{
    printf("Node\tNext Pointer\tArbit Pointer\n");
    while (node!=NULL)
    {
        cout << node->data << "\t\t";
 
        if(node->next)
            cout << node->next->data << "\t\t";
        else cout << "NULL" << "\t\t";
 
        if(node->arbit)
            cout << node->arbit->data;
        else cout << "NULL";
 
        cout << endl;
        node = node->next;
    }
}
 
/* Function to create a new node with given data */
Node *newNode(int data)
{
    Node *new_node = new Node;
    new_node->data = data;
    new_node->next = NULL;
    return new_node;
}
 
/* Driver program to test above functions*/
int main()
{
    Node *head = newNode(5);
    head->next = newNode(10);
    head->next->next = newNode(2);
    head->next->next->next = newNode(3);
 
    populateArbit(head);
 
    printf("Resultant Linked List is: \n");
    printNextArbitPointers(head);
 
    return 0;
}


Java
// Java program to point arbit pointers to highest
// value on its right
class GfG
{
 
    /* Link list node */
    static class Node
    {
        int data;
        Node next, arbit;
    }
 
    static Node maxNode;
 
    // This function populates arbit pointer in every
    // node to the greatest value to its right.
    static void populateArbit(Node head)
    {
 
        // if head is null simply return the list
        if (head == null)
            return;
 
        /* if head->next is null it means we reached at
        the last node just update the max and maxNode */
        if (head.next == null)
        {
            maxNode = head;
            return;
        }
 
        /* Calling the populateArbit to the next node */
        populateArbit(head.next);
 
        /* updating the arbit node of the current
        node with the maximum value on the right side */
        head.arbit = maxNode;
 
        /* if current Node value id greater then
        the previous right node then update it */
        if (head.data > maxNode.data)
            maxNode = head;
 
        return;
    }
 
    // Utility function to print result linked list
    static void printNextArbitPointers(Node node)
    {
        System.out.println("Node\tNext Pointer\tArbit Pointer");
        while (node != null)
        {
            System.out.print(node.data + "\t\t\t");
 
            if (node.next != null)
                System.out.print(node.next.data + "\t\t\t\t");
            else
                System.out.print("NULL" +"\t\t\t");
 
            if (node.arbit != null)
                System.out.print(node.arbit.data);
            else
                System.out.print("NULL");
 
            System.out.println();
            node = node.next;
        }
    }
 
    /* Function to create a new node with given data */
    static Node newNode(int data)
    {
        Node new_node = new Node();
        new_node.data = data;
        new_node.next = null;
        return new_node;
    }
 
    /* Driver code*/
    public static void main(String[] args)
    {
        Node head = newNode(5);
        head.next = newNode(10);
        head.next.next = newNode(2);
        head.next.next.next = newNode(3);
 
        populateArbit(head);
 
        System.out.println("Resultant Linked List is: ");
        printNextArbitPointers(head);
 
    }
}
 
// This code is contributed by shubham96301


Python3
# Python3 program to poarbit pointers to highest
# value on its right
 
''' Link list node '''
# Node class
class newNode:
 
    # Constructor to initialize the node object
    def __init__(self, data):
        self.data = data
        self.next = None
        self.arbit = None
 
# This function populates arbit pointer in every
# node to the greatest value to its right.
maxNode = newNode(None)
def populateArbit(head):
     
    # using static maxNode to keep track of maximum
    # orbit node address on right side
    global maxNode
     
    # if head is null simply return the list
    if (head == None):
        return
         
    ''' if head.next is null it means we reached at
    the last node just update the max and maxNode '''
    if (head.next == None):
        maxNode = head
        return
         
    ''' Calling the populateArbit to the next node '''
    populateArbit(head.next)
     
    ''' updating the arbit node of the current
    node with the maximum value on the right side '''
    head.arbit = maxNode
     
    ''' if current Node value id greater then
    the previous right node then update it '''
    if (head.data > maxNode.data and maxNode.data != None ):
        maxNode = head
    return
 
# Utility function to prresult linked list
def printNextArbitPointers(node):
    print("Node\tNext Pointer\tArbit Pointer")
    while (node != None):
        print(node.data,"\t\t", end = "")
        if(node.next):
            print(node.next.data,"\t\t", end = "")
        else:
            print("NULL","\t\t", end = "")
        if(node.arbit):
            print(node.arbit.data, end = "")
        else:
            print("NULL", end = "")
        print()
        node = node.next
         
''' Driver code'''
head = newNode(5)
head.next = newNode(10)
head.next.next = newNode(2)
head.next.next.next = newNode(3)
 
populateArbit(head)
 
print("Resultant Linked List is:")
printNextArbitPointers(head)
 
# This code is contributed by SHUBHAMSINGH10


C#
// C# program to point arbit pointers to highest
// value on its right
using System;
     
class GfG
{
 
    /* Link list node */
    public class Node
    {
        public int data;
        public Node next, arbit;
    }
 
    static Node maxNode;
 
    // This function populates arbit pointer in every
    // node to the greatest value to its right.
    static void populateArbit(Node head)
    {
 
        // if head is null simply return the list
        if (head == null)
            return;
 
        /* if head->next is null it means we reached at
        the last node just update the max and maxNode */
        if (head.next == null)
        {
            maxNode = head;
            return;
        }
 
        /* Calling the populateArbit to the next node */
        populateArbit(head.next);
 
        /* updating the arbit node of the current
        node with the maximum value on the right side */
        head.arbit = maxNode;
 
        /* if current Node value id greater then
        the previous right node then update it */
        if (head.data > maxNode.data)
            maxNode = head;
 
        return;
    }
 
    // Utility function to print result linked list
    static void printNextArbitPointers(Node node)
    {
        Console.WriteLine("Node\tNext Pointer\tArbit Pointer");
        while (node != null)
        {
            Console.Write(node.data + "\t\t\t");
 
            if (node.next != null)
                Console.Write(node.next.data + "\t\t\t\t");
            else
                Console.Write("NULL" +"\t\t\t");
 
            if (node.arbit != null)
                Console.Write(node.arbit.data);
            else
                Console.Write("NULL");
 
            Console.WriteLine();
            node = node.next;
        }
    }
 
    /* Function to create a new node with given data */
    static Node newNode(int data)
    {
        Node new_node = new Node();
        new_node.data = data;
        new_node.next = null;
        return new_node;
    }
 
    /* Driver code*/
    public static void Main(String[] args)
    {
        Node head = newNode(5);
        head.next = newNode(10);
        head.next.next = newNode(2);
        head.next.next.next = newNode(3);
 
        populateArbit(head);
 
        Console.WriteLine("Resultant Linked List is: ");
        printNextArbitPointers(head);
 
    }
}
 
/* This code contributed by PrinciRaj1992 */


Javascript


输出:

Resultant Linked List is: 
Node    Next Pointer    Arbit Pointer
5               10              10
10              2               3
2               3               3
3               NULL            NULL


递归解决方案:
我们可以递归地到达最后一个节点,并从末尾遍历链表。递归解决方案不需要反转链表。我们还可以使用堆栈代替递归来临时保存节点。感谢 Santosh Kumar Mishra 提供此解决方案。

C++

// C++ program to point arbit pointers to highest
// value on its right
#include
using namespace std;
 
/* Link list node */
struct Node
{
    int data;
    Node* next, *arbit;
};
 
// This function populates arbit pointer in every
// node to the greatest value to its right.
void populateArbit(Node *head)
{
    // using static maxNode to keep track of maximum
    // orbit node address on right side
    static Node *maxNode;
 
    // if head is null simply return the list
    if (head == NULL)
        return;
 
    /* if head->next is null it means we reached at
       the last node just update the max and maxNode */
    if (head->next == NULL)
    {
        maxNode = head;
        return;
    }
 
    /* Calling the populateArbit to the next node */
    populateArbit(head->next);
 
    /* updating the arbit node of the current
     node with the maximum value on the right side */
    head->arbit = maxNode;
 
    /* if current Node value id greater then
     the previous right node then  update it */
    if (head->data > maxNode->data)
        maxNode = head;
 
   return;
}
 
// Utility function to print result linked list
void printNextArbitPointers(Node *node)
{
    printf("Node\tNext Pointer\tArbit Pointer\n");
    while (node!=NULL)
    {
        cout << node->data << "\t\t";
 
        if(node->next)
            cout << node->next->data << "\t\t";
        else cout << "NULL" << "\t\t";
 
        if(node->arbit)
            cout << node->arbit->data;
        else cout << "NULL";
 
        cout << endl;
        node = node->next;
    }
}
 
/* Function to create a new node with given data */
Node *newNode(int data)
{
    Node *new_node = new Node;
    new_node->data = data;
    new_node->next = NULL;
    return new_node;
}
 
/* Driver program to test above functions*/
int main()
{
    Node *head = newNode(5);
    head->next = newNode(10);
    head->next->next = newNode(2);
    head->next->next->next = newNode(3);
 
    populateArbit(head);
 
    printf("Resultant Linked List is: \n");
    printNextArbitPointers(head);
 
    return 0;
}

Java

// Java program to point arbit pointers to highest
// value on its right
class GfG
{
 
    /* Link list node */
    static class Node
    {
        int data;
        Node next, arbit;
    }
 
    static Node maxNode;
 
    // This function populates arbit pointer in every
    // node to the greatest value to its right.
    static void populateArbit(Node head)
    {
 
        // if head is null simply return the list
        if (head == null)
            return;
 
        /* if head->next is null it means we reached at
        the last node just update the max and maxNode */
        if (head.next == null)
        {
            maxNode = head;
            return;
        }
 
        /* Calling the populateArbit to the next node */
        populateArbit(head.next);
 
        /* updating the arbit node of the current
        node with the maximum value on the right side */
        head.arbit = maxNode;
 
        /* if current Node value id greater then
        the previous right node then update it */
        if (head.data > maxNode.data)
            maxNode = head;
 
        return;
    }
 
    // Utility function to print result linked list
    static void printNextArbitPointers(Node node)
    {
        System.out.println("Node\tNext Pointer\tArbit Pointer");
        while (node != null)
        {
            System.out.print(node.data + "\t\t\t");
 
            if (node.next != null)
                System.out.print(node.next.data + "\t\t\t\t");
            else
                System.out.print("NULL" +"\t\t\t");
 
            if (node.arbit != null)
                System.out.print(node.arbit.data);
            else
                System.out.print("NULL");
 
            System.out.println();
            node = node.next;
        }
    }
 
    /* Function to create a new node with given data */
    static Node newNode(int data)
    {
        Node new_node = new Node();
        new_node.data = data;
        new_node.next = null;
        return new_node;
    }
 
    /* Driver code*/
    public static void main(String[] args)
    {
        Node head = newNode(5);
        head.next = newNode(10);
        head.next.next = newNode(2);
        head.next.next.next = newNode(3);
 
        populateArbit(head);
 
        System.out.println("Resultant Linked List is: ");
        printNextArbitPointers(head);
 
    }
}
 
// This code is contributed by shubham96301   

蟒蛇3

# Python3 program to poarbit pointers to highest
# value on its right
 
''' Link list node '''
# Node class
class newNode:
 
    # Constructor to initialize the node object
    def __init__(self, data):
        self.data = data
        self.next = None
        self.arbit = None
 
# This function populates arbit pointer in every
# node to the greatest value to its right.
maxNode = newNode(None)
def populateArbit(head):
     
    # using static maxNode to keep track of maximum
    # orbit node address on right side
    global maxNode
     
    # if head is null simply return the list
    if (head == None):
        return
         
    ''' if head.next is null it means we reached at
    the last node just update the max and maxNode '''
    if (head.next == None):
        maxNode = head
        return
         
    ''' Calling the populateArbit to the next node '''
    populateArbit(head.next)
     
    ''' updating the arbit node of the current
    node with the maximum value on the right side '''
    head.arbit = maxNode
     
    ''' if current Node value id greater then
    the previous right node then update it '''
    if (head.data > maxNode.data and maxNode.data != None ):
        maxNode = head
    return
 
# Utility function to prresult linked list
def printNextArbitPointers(node):
    print("Node\tNext Pointer\tArbit Pointer")
    while (node != None):
        print(node.data,"\t\t", end = "")
        if(node.next):
            print(node.next.data,"\t\t", end = "")
        else:
            print("NULL","\t\t", end = "")
        if(node.arbit):
            print(node.arbit.data, end = "")
        else:
            print("NULL", end = "")
        print()
        node = node.next
         
''' Driver code'''
head = newNode(5)
head.next = newNode(10)
head.next.next = newNode(2)
head.next.next.next = newNode(3)
 
populateArbit(head)
 
print("Resultant Linked List is:")
printNextArbitPointers(head)
 
# This code is contributed by SHUBHAMSINGH10

C#

// C# program to point arbit pointers to highest
// value on its right
using System;
     
class GfG
{
 
    /* Link list node */
    public class Node
    {
        public int data;
        public Node next, arbit;
    }
 
    static Node maxNode;
 
    // This function populates arbit pointer in every
    // node to the greatest value to its right.
    static void populateArbit(Node head)
    {
 
        // if head is null simply return the list
        if (head == null)
            return;
 
        /* if head->next is null it means we reached at
        the last node just update the max and maxNode */
        if (head.next == null)
        {
            maxNode = head;
            return;
        }
 
        /* Calling the populateArbit to the next node */
        populateArbit(head.next);
 
        /* updating the arbit node of the current
        node with the maximum value on the right side */
        head.arbit = maxNode;
 
        /* if current Node value id greater then
        the previous right node then update it */
        if (head.data > maxNode.data)
            maxNode = head;
 
        return;
    }
 
    // Utility function to print result linked list
    static void printNextArbitPointers(Node node)
    {
        Console.WriteLine("Node\tNext Pointer\tArbit Pointer");
        while (node != null)
        {
            Console.Write(node.data + "\t\t\t");
 
            if (node.next != null)
                Console.Write(node.next.data + "\t\t\t\t");
            else
                Console.Write("NULL" +"\t\t\t");
 
            if (node.arbit != null)
                Console.Write(node.arbit.data);
            else
                Console.Write("NULL");
 
            Console.WriteLine();
            node = node.next;
        }
    }
 
    /* Function to create a new node with given data */
    static Node newNode(int data)
    {
        Node new_node = new Node();
        new_node.data = data;
        new_node.next = null;
        return new_node;
    }
 
    /* Driver code*/
    public static void Main(String[] args)
    {
        Node head = newNode(5);
        head.next = newNode(10);
        head.next.next = newNode(2);
        head.next.next.next = newNode(3);
 
        populateArbit(head);
 
        Console.WriteLine("Resultant Linked List is: ");
        printNextArbitPointers(head);
 
    }
}
 
/* This code contributed by PrinciRaj1992 */

Javascript


输出:

Resultant Linked List is: 
Node    Next Pointer    Arbit Pointer
5               10              10
10              2               3
2               3               3
3               NULL            NULL

如果您希望与专家一起参加现场课程,请参阅DSA 现场工作专业课程学生竞争性编程现场课程