Linux learning Summary (Data Structure 2-Joseph's ring)

Loop linked list, the final tail pointer pointing to the head knot point, two-way loop linked list is to add a pre pointer.

Questions about Joseph's ring: set N people numbered 1, 2, 3,... n to sit in a circle. The person whose sequence number is K (1 <= k <= N) starts counting from 1. The person whose number is m is listed, and his next digit starts counting from 1, those who count to m are listed again, and so on until all people are listed.

For example, if n = 8, K = 3, M = 4, the column sequence is: 6 2 7 4 3 5 1 8.

Algorithm idea: Use a circular linked list with no leading nodes to deal with the problem of Joseph Phu: first form a single circular linked list with N nodes, and then count from 1 on the K node, when M is recorded, the corresponding node is deleted from the linked list, and then counted from 1 starting from the next node of the deleted node ....., the algorithm ends until all nodes are listed.

#include <stdio.h>#include <errno.h>#include <stdlib.h>#define N 10typedef int datatype;typedef struct node {    datatype data;    struct node * next;}linknode ,*linklist;linklist create(){    linklist H;    if((H = (linklist)malloc(sizeof(linknode)))==NULL)    {        perror("malloc");        exit(-1);    }    H->next = H;    H->data = 1;    printf("create\n");    return H;}int insert(linklist H,datatype data , int pos){    int i;    linklist q;    linklist p = NULL;    p = H;    if((pos<0))    {        printf("insert error\n");        return -1;    }    if((q = (linklist)malloc(sizeof(linknode))) == NULL )    {        perror("malloc");        exit(-1);    }    while(pos--)    p=p->next;    q->data = data;     q->next = p->next;    p->next = q;    return 0;}int show(linklist H,int k,int m){    int i = k-2;    linklist p,q;    p = H;    while(i--) p = p->next;    while(p != p->next)    {    for(i = 0;i < m-1; i++)        p = p->next;        q = p;        p = p->next;        q ->next = p->next;        printf("data =%d\n",p->data);        free(p);        p = q->next;    }    printf("data =%d\n",p->data);    return 0;}int main(int argc,char * argv[]){     int n,m,k,i = 0;    int ret;    linklist H;    H = create();    scanf("%d",&n);    scanf("%d",&m);    scanf("%d",&k);    for(i = 2;i < n+1;i++)    {    ret = insert(H,i,i-2);    if(ret ==-1)        printf("insert error\n");    }    printf("**********create linklist*************\n");    show(H,m,k);    return 0;}