用c语言写出实验题目1的代码，输入任何多项式都能保证运行

以下是使用C语言实现的一元稀疏多项式的基本操作的示例代码。该代码实现了多项式的创建、销毁、输出、加法和减法功能。为了简洁起见，这里假设多项式的系数和指数都是整数。

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

typedef struct Node {
    int coef;  // 系数
    int exp;   // 指数
    struct Node *next;
} PolyNode;

// 创建一个新节点
PolyNode* createNode(int coef, int exp) {
    PolyNode *newNode = (PolyNode*)malloc(sizeof(PolyNode));
    newNode->coef = coef;
    newNode->exp = exp;
    newNode->next = NULL;
    return newNode;
}

// 销毁多项式
void destroyPoly(PolyNode *head) {
    while (head != NULL) {
        PolyNode *temp = head;
        head = head->next;
        free(temp);
    }
}

// 插入节点到多项式中
void insertNode(PolyNode **head, int coef, int exp) {
    PolyNode *newNode = createNode(coef, exp);
    if (*head == NULL || (*head)->exp < exp) {
        newNode->next = *head;
        *head = newNode;
    } else {
        PolyNode *current = *head;
        while (current->next != NULL && current->next->exp > exp) {
            current = current->next;
        }
        if (current->next != NULL && current->next->exp == exp) {
            current->next->coef += coef;
            if (current->next->coef == 0) {
                PolyNode *temp = current->next;
                current->next = temp->next;
                free(temp);
            }
        } else {
            newNode->next = current->next;
            current->next = newNode;
        }
    }
}

// 输出多项式
void printPoly(PolyNode *head) {
    if (head == NULL) {
        printf("0\n");
        return;
    }
    for (PolyNode *p = head; p != NULL; p = p->next) {
        if (p != head) {
            if (p->coef > 0) {
                printf(" + ");
            } else {
                printf(" - ");
                p->coef = -p->coef;
            }
        }
        if (p->exp == 0) {
            printf("%d", p->coef);
        } else if (p->exp == 1) {
            if (p->coef != 1) {
                printf("%dx", p->coef);
            } else {
                printf("x");
            }
        } else {
            if (p->coef != 1) {
                printf("%dx^%d", p->coef, p->exp);
            } else {
                printf("x^%d", p->exp);
            }
        }
    }
    printf("\n");
}

// 多项式相加
PolyNode* addPoly(PolyNode *poly1, PolyNode *poly2) {
    PolyNode *result = NULL;
    while (poly1 != NULL && poly2 != NULL) {
        if (poly1->exp > poly2->exp) {
            insertNode(&result, poly1->coef, poly1->exp);
            poly1 = poly1->next;
        } else if (poly1->exp < poly2->exp) {
            insertNode(&result, poly2->coef, poly2->exp);
            poly2 = poly2->next;
        } else {
            int sum = poly1->coef + poly2->coef;
            if (sum != 0) {
                insertNode(&result, sum, poly1->exp);
            }
            poly1 = poly1->next;
            poly2 = poly2->next;
        }
    }
    while (poly1 != NULL) {
        insertNode(&result, poly1->coef, poly1->exp);
        poly1 = poly1->next;
    }
    while (poly2 != NULL) {
        insertNode(&result, poly2->coef, poly2->exp);
        poly2 = poly2->next;
    }
    return result;
}

// 多项式相减
PolyNode* subPoly(PolyNode *poly1, PolyNode *poly2) {
    PolyNode *negPoly2 = NULL;
    for (PolyNode *p = poly2; p != NULL; p = p->next) {
        insertNode(&negPoly2, -p->coef, p->exp);
    }
    return addPoly(poly1, negPoly2);
}

int main() {
    PolyNode *poly1 = NULL;
    PolyNode *poly2 = NULL;

    // 输入多项式1
    int n1;
    printf("Enter the number of terms in polynomial 1: ");
    scanf("%d", &n1);
    for (int i = 0; i < n1; i++) {
        int coef, exp;
        printf("Enter coefficient and exponent: ");
        scanf("%d %d", &coef, &exp);
        insertNode(&poly1, coef, exp);
    }

    // 输入多项式2
    int n2;
    printf("Enter the number of terms in polynomial 2: ");
    scanf("%d", &n2);
    for (int i = 0; i < n2; i++) {
        int coef, exp;
        printf("Enter coefficient and exponent: ");
        scanf("%d %d", &coef, &exp);
        insertNode(&poly2, coef, exp);
    }

    // 输出多项式
    printf("Polynomial 1: ");
    printPoly(poly1);
    printf("Polynomial 2: ");
    printPoly(poly2);

    // 多项式相加
    PolyNode *sum = addPoly(poly1, poly2);
    printf("Sum: ");
    printPoly(sum);

    // 多项式相减
    PolyNode *diff = subPoly(poly1, poly2);
    printf("Difference: ");
    printPoly(diff);

    // 销毁多项式
    destroyPoly(poly1);
    destroyPoly(poly2);
    destroyPoly(sum);
    destroyPoly(diff);

    return 0;
}

### 说明
1. **创建节点**：`createNode` 函数用于创建新的多项式节点。
2. **插入节点**：`insertNode` 函数将节点按指数降序插入多项式链表中，并处理相同指数的合并。
3. **销毁多项式**：`destroyPoly` 函数释放多项式链表占用的内存。
4. **输出多项式**：`printPoly` 函数以标准形式输出多项式。
5. **多项式相加**：`addPoly` 函数实现两个多项式的相加。
6. **多项式相减**：`subPoly` 函数通过先取第二个多项式的负值再相加来实现相减。

### 使用方法
1. 运行程序后，首先输入第一个多项式的项数。
2. 输入每个项的系数和指数。
3. 同样步骤输入第二个多项式的项数和每个项的系数和指数。
4. 程序会输出两个多项式、它们的和与差。

希望这段代码能满足您的需求！如果有任何问题或需要进一步的帮助，请随时告诉我。