#include"slist.h" void InitList(List *list) { list->first = list->last = (Node*) malloc ( sizeof (Node)); //头结点 assert (list->first != NULL); list->first->next = NULL; list->size = 0; } //push_back的优化 void push_back(List *list, ElemType x) { insert(list, end(list), x); } //push_front的优化 void push_front(List *list, ElemType x) { insert(list, begin(list), x); } void show_list(List *list) { //step 1:指针p指向单链表的第一个结点 Node *p = list->first->next; //step 2:循环打印结点的信息 while (p != NULL) { printf ( "%d->" , p->data); p = p->next; } printf ( "Nul.\n" ); } void pop_back(List *list) { //step 1:判断单链表是否为空 if (list->size == 0) return ; //step 2:定义指针p使其指向目标结点的前一个结点 Node *p = list->first; //从头结点开始 while (p->next != list->last) p = p->next; //step 3:删除目标结点 free (list->last); list->last = p; list->last->next = NULL; //step 4:更新单链表的长度 list->size--; } void pop_front(List *list) { //step 1:判断单链表是否为空 if (list->size == 0) return ; //step 2:定义指针p使其指向目标结点的前一个结点 Node *p = list->first->next; //step 3:删除目标结点 list->first->next = p->next; free (p); //step 4:判断删除的结点是否是单链表的最后一个结点,若是则更新单链表的尾指针 if (list->size == 1) list->last = list->first; //step 4:更新单链表的长度 list->size--; } //insert_val的优化 void insert_val(List *list, ElemType x) { //step 1:创建一个新的结点 Node *s = CreateNode(x); //step 2:定义指针p使其指向待插入位置的前一个结点 Node *p = list->first; //从头结点开始 while (p->next != NULL && p->next->data < s->data) p = p->next; //step 3:判断结点的待插入位置是否是表尾,若是则更新单链表的尾指针 if (p->next == NULL) list->last = s; //step 4:插入结点 s->next = p->next; p->next = s; //step 5:更新单链表长度 list->size++; } Node* find(List *list, ElemType x) { //step 1:指针p指向单链表的第一个结点 Node *p = list->first->next; //step 2:按照循环顺序查找链表结点 while (p != NULL && p->data != x) p = p->next; return p; } int length(List *list) { return list->size; } void delete_val(List *list, ElemType x) { //step 1:判断单链表是否为空 if (list->size == 0) return ; //step 2:确定结点在单链表中的位置,并判断其是否存在于单链表中 Node *p = find(list, x); if (p == NULL) { printf ( "要删除的数据不存在!\n" ); return ; } //step 3:判断结点位置是否是表尾 if (p == list->last) //是表尾 pop_back(list); else { //不是表尾 Node *q = p->next; p->data = q->data; p->next = q->next; free (q); list->size--; } } void sort(List *list) { //step 1:判断单链表中的结点数是否为0或1 if (list->size == 0 || list->size == 1) return ; //step 2:将单链表中第一个结点之后的链表部分截出,方便重新按顺序插入链表之中 Node *s = list->first->next; // 指针s指向单链表的第一个节点 Node *p = s->next; //q指向s后面的结点 list->last = s; //单链表的尾指针指向单链表的第一个结点 list->last->next = NULL; //截断链表 //step 3:将截出的链表中的结点根据其数据域大小重新插入到原来链表中 while (p != NULL) { s = p; p = p->next; Node *q = list->first; while (q->next != NULL && q->next->data < s->data) q = q->next; if (q->next == NULL) //判断q此时指向的是否是单链表的最后一个结点,若是则更新链表的尾指针 list->last = s; //将结点重新插入链表 s->next = q->next; q->next = s; } } void reverse(List *list) { //step 1:判断单链表中的结点数是否为0或1 if (list->size == 0 || list->size == 1) return ; //step 2:将单链表中第一个结点之后的链表部分截出,然后将截出的链表中的结点按头插法重新插入到原链表中 Node *p = list->first->next; Node *q = p->next; list->last = p; list->last->next = NULL; while (q != NULL) { p = q; q = q->next; p->next = list->first->next; list->first->next = p; } } void clear(List *list) { //step 1:判断单链表是否为空 if (list->size == 0) return ; //step 2:释放单链表中的每一个结点 Node *p = list->first->next; while (p != NULL) { list->first->next = p->next; free (p); p = list->first->next; } //step 3:头指针和尾指针重新都指向头结点 list->last = list->first; //step 4:更新链表长度 list->size = 0; } void destroy(List *list) { //step 1:清空单链表 clear(list); //step 2:释放头结点 free (list->first); //step 3:头指针和尾指针都赋值为空 list->first = list->last = NULL; } //优化 Node* CreateNode(ElemType x) { Node *s = (Node*) malloc ( sizeof (Node)); assert (s != NULL); s->data = x; s->next = NULL; return s; } Node* begin(List *list) { return list->first->next; } Node* end(List *list) { return list->last->next; } void insert(List *list, Node *pos, ElemType x) { //step 1:创建一个新的结点 Node *s = CreateNode(x); //step 2:确定带插入位置 Node *p = list->first; while (p->next != pos) p = p->next; //step 3:插入结点 s->next = p->next; p->next = s; //step 4:判断结点是否插入到链表的表尾,若是则更新单链表的表尾指针 if (pos == NULL) list->last = s; //step 5:更新单链表长度 list->size++; } |