176 lines
3.0 KiB
C
176 lines
3.0 KiB
C
#include <stdio.h>
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#include <stdbool.h>
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struct single_list {
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struct single_list *next;
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int val;
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};
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struct single_list_head {
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struct single_list *head;
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};
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bool is_empty(struct single_list_head *head)
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{
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return head->head == NULL;
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}
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void dump(struct single_list_head *head)
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{
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struct single_list *tmp = head->head;
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int idx = 0;
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while (tmp) {
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printf("[%02d]: %08d\n", idx++, tmp->val);
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tmp = tmp->next;
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}
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}
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void insert(struct single_list **prev, struct single_list *elem)
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{
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if (!prev)
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return;
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if (*prev)
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elem->next = *prev;
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*prev = elem;
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}
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void insert_head(struct single_list_head *head, struct single_list *elem)
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{
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insert(&head->head, elem);
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}
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struct single_list* del(struct single_list **prev)
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{
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struct single_list *tmp;
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if (!prev)
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return NULL;
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tmp = *prev;
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*prev = (*prev)->next;
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tmp->next = NULL;
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return tmp;
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};
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struct single_list* delete_head(struct single_list_head* head)
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{
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return del(&head->head);
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};
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struct single_list** search(struct single_list_head* head, int target)
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{
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struct single_list **prev, *tmp;
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for (prev = &head->head, tmp = *prev;
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tmp && (tmp->val < target);
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prev = &tmp->next, tmp = *prev)
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;
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return prev;
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};
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void reverse(struct single_list_head* head)
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{
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struct single_list_head tmp;
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struct single_list *elem;
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while (!is_empty(head)) {
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elem = delete_head(head);
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insert_head(&tmp, elem);
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}
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head->head = tmp.head;
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}
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bool is_cyclic(struct single_list_head* head)
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{
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struct single_list *s1, *s2;
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s1 = s2 = head->head;
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while(s1 && s2) {
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s1 = s1->next;
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s2 = s2->next ? s2->next->next:s2->next;
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if (s1 == s2)
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return true;
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}
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return false;
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}
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struct single_list* middle(struct single_list_head* head)
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{
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struct single_list *s1, *s2;
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struct single_list pseudo_head;
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pseudo_head.next = head->head;
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s1 = s2 = &pseudo_head;
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while (true) {
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if (!s2 || !s2->next)
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return s1;
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s1 = s1->next;
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s2 = s2->next->next;
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}
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return NULL;
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};
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int main()
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{
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struct single_list_head head = {NULL};
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struct single_list lists[10];
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struct single_list **prev;
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int idx;
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for (idx = 0; idx < 10; idx++) {
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lists[idx].val = idx;
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lists[idx].next = NULL;
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}
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insert_head(&head, &lists[6]);
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insert_head(&head, &lists[5]);
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insert_head(&head, &lists[4]);
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insert_head(&head, &lists[1]);
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insert_head(&head, &lists[0]);
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printf("=== insert 0, 1, 4, 5, 6\n");
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dump(&head);
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prev = search(&head, 2);
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insert(prev, &lists[2]);
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printf("=== insert 2\n");
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dump(&head);
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printf("middle elem is %d\n", middle(&head)->val);
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prev = search(&head, 2);
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if ((*prev) && ((*prev)->val == 2))
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printf("The list contains 2\n");
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else
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printf("The list not contains 2\n");
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del(prev);
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prev = search(&head, 2);
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printf("After remove 2\n");
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if ((*prev) && ((*prev)->val == 2))
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printf("The list contains 2\n");
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else
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printf("The list not contains 2\n");
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dump(&head);
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printf("After reverse \n");
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reverse(&head);
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dump(&head);
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printf("middle elem is %d\n", middle(&head)->val);
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lists[0].next = &lists[6];
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printf("list is%s cyclic\n", is_cyclic(&head)?"":" not");
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return 0;
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}
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