C語言拆分迴圈連結串列程式

建立一個迴圈連結串列，並將這個迴圈連結串列拆分成為兩個迴圈連結串列的範例程式，將以下程式碼儲存到一個原始檔中：split_circular_linked_list.c， 如下所示 -

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

struct node {
    int data;
    struct node *next;
};

struct node *even = NULL;
struct node *odd = NULL;
struct node *list = NULL;

//Create Linked List
void insert(int data) {
    // Allocate memory for new node;
    struct node *link = (struct node*) malloc(sizeof(struct node));
    struct node *current;

    link->data = data;
    link->next = NULL;

    if (list == NULL) {
        list = link;
        list->next = link;
        return;
    }
    current = list;

    while (current->next != list)
        current = current->next;

    // Insert link at the end of the list
    current->next = link;
    link->next = list;
}

void display(struct node *head) {
    struct node *ptr = head;

    printf("[head] =>");
    //start from the beginning
    while (ptr->next != head) {
        printf(" %d =>", ptr->data);
        ptr = ptr->next;
    }
    printf(" %d =>", ptr->data);
    printf(" [head]\n");
}

void split_list() {
    int count = 0;
    // Allocate memory for new node;
    struct node *list1;
    struct node *link;
    struct node *current;

    list1 = list;


    while (list1->next != list) {
        struct node *link = (struct node*) malloc(sizeof(struct node));

        link->data = list1->data;
        link->next = NULL;

        if (list1->data % 2 == 0) {

            if (even == NULL) {
                even = link;
                even->next = link;
                list1 = list1->next;
                continue;
            }
            else {
                current = even;

                while (current->next != even) {
                    current = current->next;
                }

                // Insert link at the end of the list
                current->next = link;
                link->next = even;
            }
            list1 = list1->next;
        }
        else {
            if (odd == NULL) {
                odd = link;
                odd->next = link;
                list1 = list1->next;
                continue;
            }
            else {
                current = odd;

                while (current->next != odd) {
                    current = current->next;
                }
                // Insert link at the end of the list
                current->next = link;
                link->next = odd;

            }
            list1 = list1->next;
        }
    }
    // Lets handle the last node
    link = (struct node*) malloc(sizeof(struct node));

    link->data = list1->data;
    link->next = NULL;
    if (list1->data % 2 == 0) {
        current = even;

        while (current->next != even) {
            current = current->next;
        }

        // Insert link at the end of the list
        current->next = link;
        link->next = even;
    }
    else {
        current = odd;

        while (current->next != odd) {
            current = current->next;
        }
        // Insert link at the end of the list
        current->next = link;
        link->next = odd;
    }
}

int main() {
    int i;

    for (i = 1; i <= 10; i++)
        insert(i);

    printf("Complete list: \n");
    display(list);

    split_list();

    printf("\nOdd  : ");
    display(odd);

    printf("Even : ");
    display(even);

    return 0;
}

執行上面程式，得到以下結果 -

Complete list:
[head] => 1 => 2 => 3 => 4 => 5 => 6 => 7 => 8 => 9 => 10 => [head]

Odd  : [head] => 1 => 3 => 5 => 7 => 9 => [head]
Even : [head] => 2 => 4 => 6 => 8 => 10 => [head]