分别用C语言和C++解决该问题

在C语言中，你可以使用指针和动态内存分配来构建这个链表，以下是基本的代码实现：

#include <stdio.h>
#include <stdlib.h>

typedef struct Node {
    int num;
    int score;
    struct Node* next;
} Node;

Node* create_linked_list(char* input) {
    char* data = strtok(input, ",");
    Node* head = (Node*)malloc(sizeof(Node));
    head->num = atoi(data);
    head->score = atoi(strtok(NULL, ","));
    head->next = NULL;

    while (data != NULL) {
        data = strtok(NULL, ",");
        Node* newNode = (Node*)malloc(sizeof(Node));
        newNode->num = atoi(data);
        newNode->score = atoi(strtok(NULL, ","));

        newNode->next = head->next;
        head->next = newNode;
    }

    return head;
}

// 输出链表
void print_list(Node* head) {
    Node* temp = head;
    while (temp != NULL) {
        printf("[num=%d,score=%d] -> ", temp->num, temp->score);
        temp = temp->next;
    }
    printf("NULL\n");
}

int main() {
    char input[] = "201,98,202,94,203,89";
    Node* list = create_linked_list(input);
    print_list(list);
    free(list); // 注意释放内存
    return 0;
}

在C++中，可以使用标准模板库(STL)中的`std::list`来更简洁地表示链表，以下是代码示例：

#include <iostream>
#include <sstream>
#include <vector>

struct Node {
    int num;
    int score;
    Node* next;
};

Node* create_linked_list(std::string input) {
    std::istringstream iss(input);
    std::vector<std::string> tokens;
    std::getline(iss, tokens[0]); // 获取头节点
    Node* head = new Node{stoi(tokens[0].substr(tokens[0].find_last_of(".") + 1)), stoi(tokens[0].substr(0, tokens[0].find_last_of("."))), nullptr};
    
    for (size_t i = 1; i < tokens.size(); i += 2) {
        Node* newNode = new Node{stoi(tokens[i].substr(tokens[i].find_last_of(".") + 1)), stoi(tokens[i].substr(0, tokens[i].find_last_of(".")))};
        newNode->next = head->next;
        head->next = newNode;
    }
    return head;
}

void print_list(Node* head) {
    Node* temp = head;
    while (temp) {
        std::cout << "[num=" << temp->num << ",score=" << temp->score << "]" << " -> ";
        temp = temp->next;
    }
    std::cout << "NULL" << std::endl;
}

int main() {
    std::string input = "201,98,202,94,203,89";
    Node* list = create_linked_list(input);
    print_list(list);
    delete list; // 注意释放内存
    return 0;
}

以上代码都假设了输入的字符串格式已经预处理过，只包含有效的学号和成绩。