实验11-2-8 单链表结点删除 (20分)
本题要求实现两个函数,分别将读入的数据存储为单链表、将链表中所有存储了某给定值的结点删除。链表结点定义如下:
struct ListNode {
int data;
ListNode *next;
};
函数接口定义:
struct ListNode *readlist();
struct ListNode *deletem( struct ListNode *L, int m );
函数readlist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deletem将单链表L中所有存储了m的结点删除。返回指向结果链表头结点的指针。
裁判测试程序样例:
#include <stdio.h>
#include <stdlib.h>
struct ListNode {
int data;
struct ListNode *next;
};
struct ListNode *readlist();
struct ListNode *deletem( struct ListNode *L, int m );
void printlist( struct ListNode *L )
{
struct ListNode *p = L;
while (p) {
printf("%d ", p->data);
p = p->next;
}
printf("\n");
}
int main()
{
int m;
struct ListNode *L = readlist();
scanf("%d", &m);
L = deletem(L, m);
printlist(L);
return 0;
}
输入样例:
10 11 10 12 10 -1
10
输出样例:
11 12
struct ListNode *readlist()
{
struct ListNode *p, *head = NULL, *tail;
int x;
scanf("%d",&x);
while(x != -1)
{
p = (struct ListNode*)malloc(sizeof(struct ListNode));
p -> data = x;
p -> next = NULL;
if(head == NULL) head = p;
else tail -> next = p;
tail = p;
scanf("%d", &x);
}
return head;
}
struct ListNode *deletem( struct ListNode *L, int m )
{
struct ListNode *tail, *p;
while(L!=NULL && L->data == m )
{
p = L;
L = L->next;
free(p);
}
if(L == NULL)
return NULL;
p = L;
tail = p -> next;
while(tail != NULL)
{
if(tail->data == m)
{
p->next = tail->next;
free(tail);
}
else p = tail;
tail = p -> next;
}
return L;
}