PTA: 删除单链表偶数节点(C语言)

柔情只为你懂 2023-07-25 14:16 5阅读 0赞

本题要求实现两个函数，分别将读入的数据存储为单链表、将链表中偶数值的结点删除。链表结点定义如下：

struct ListNode \{  
int data;  
struct ListNode \*next;  
\};

函数接口定义：  
struct ListNode \*createlist();  
struct ListNode \*deleteeven( struct ListNode \*head );

函数createlist从标准输入读入一系列正整数，按照读入顺序建立单链表。当读到−1时表示输入结束，函数应返回指向单链表头结点的指针。

函数deleteeven将单链表head中偶数值的结点删除，返回结果链表的头指针。

裁判测试程序样例：  
\#include <stdio.h>  
\#include <stdlib.h>

struct ListNode \{  
int data;  
struct ListNode \*next;  
\};

struct ListNode \*createlist();  
struct ListNode \*deleteeven( struct ListNode \*head );  
void printlist( struct ListNode \*head )  
\{  
struct ListNode \*p = head;  
while § \{  
printf("%d “, p->data);  
p = p->next;  
\}  
printf(”\\n");  
\}

int main()  
\{  
struct ListNode \*head;

head = createlist();  
head = deleteeven(head);  
printlist(head);

return 0;  
\}

/\* 你的代码将被嵌在这里 \*/

输入样例：  
1 2 2 3 4 5 6 7 -1

输出样例：  
1 3 5 7

struct ListNode *createlist()
    { 
        int temp;
        struct ListNode *head, *p, *tail;
    
        head = (struct ListNode*)malloc(sizeof(struct ListNode));
        head->next = NULL;
        tail = head;
        while (1)
        { 
            scanf("%d", &temp);
            if (temp == -1)
                break;
            p = (struct ListNode*)malloc(sizeof(struct ListNode));
            p->next = NULL;
            p->data = temp;
            tail->next = p;
            tail = p;
        }
    
        return head->next;
    }
    struct ListNode *deleteeven( struct ListNode *head )
    { 
        struct ListNode *p, *q, *OddHead;
    
        OddHead = head;
        while ((OddHead->data % 2) == 0)
        { 
            OddHead = OddHead->next;
            if (OddHead == NULL)
                break;
        }
        p = OddHead;
        while (p != NULL)
        { 
            if ((p->data % 2) == 0)
            { 
                q->next = p->next;
                p = p->next;
                continue;
            }
            q = p;
            p = p->next;
        }
    
        return OddHead;
    }