Link List

At first, i prepared to go through 《the introduction to algorithm》 ,however , i found some part of the book is difficult to understand; what’s more , i can’t borrow the book in the library. Then i found another book, 《algorithm in C》，which reveal most basic idea of some classical algorithm, so i decide to read this book firstly.

example 1:josephus funciton

#include<stdlib.h>

#include<stdio.h>

typedef struct node* link;

struct node

{

    int item;

    link next;

};



int main(int argc,char *argv[])

{

    int i, N, M;

    scanf("%d%d",&N,&M);

    node *t = new node,*x;

    x = t;

    t->item = 1;

    t->next = t;

    for (i = 2; i <= N; i++)

    {

        x->next = new node;

        x = x->next;

        x->item = i;

        x->next = t;

    }

    while (x != x->next)

    {

        for (i = 1; i < M; i++)

        {

            x = x->next;

        }

        x->next = x->next->next;

        N--;

    }

    printf("%d\n",x->item);

}

example2: reverse link list

#include<stdlib.h>

#include<stdio.h>

typedef struct node* link;

struct node

{

    int item;

    link next;

    node()

    {

        next = NULL;

    }

};



link reverse(link x)

{

    /*

    将y后节点的指针保存在t中，然后将y的链接指向r,再使r移到y,y移到t

    */

    link t, y = x, r = NULL;

    while (y != NULL)

    {

        t = y->next;

        y->next = r;

        r = y;

        y = t;

    }

    return r;

}



int main(int argc,char *argv[])

{

    int i, N, M;

    scanf("%d%d",&N,&M);

    node *t = new node,*x,*head;

    x = t;

    head = t;

    t->item = 1;

    t->next = t;

    for (i = 2; i <= N; i++)

    {

        x->next = new node;

        x = x->next;

        x->item = i;

    }

    node *newhead = reverse(head);

    while (newhead != NULL)

    {

        printf("%d ",newhead->item);

        newhead = newhead->next;

    }

}