链表 插入排序

参考了几个网上例子，验证后发现，不是最后几个元素会产生环，要么就是排序后不是稳定的（相同key值的元素，会意外改变顺序）

最后自己写了个例子，用了2种方法写基于链表的插入排序,

#include <stdio.h>
#include <stdlib.h>
#define null 0

struct node;
struct node{
    struct node *n;
    void *d;
    int k;
    int val;
};

typedef struct node nod;

struct node* init(int size, int *val){
    struct node *head = malloc(sizeof(struct node));
    struct node *c = head;
    head->k = 0;
    for(int i = 0; i < size; i++){
        struct node *n= malloc(sizeof(struct node));
        n->k = val[i];
        n->val = i;
        c->n = n;
        c = n;
    }
    c=head->n;
    free(head);
    return c;
}

void print_n(struct node *n){
    while(n != null){
        printf("%d(%d) -> ",n->k,n->val);
        n = n->n;
    }
    printf("
");
}


nod* insert_sort3(nod *h){
    nod *pre;
    nod *p,*cur,*n;
    nod *dummy = malloc(sizeof(nod));
    dummy->n = h;
    p=dummy;
    //pre=dummy;
    cur=h;
    //n=h;

    while(cur != null){
        n = cur->n;
        pre = dummy;
        while(pre != null && pre->n != null && pre->n->k <= cur->k && pre->n != cur){// stabilize
            pre = pre->n;
        }
        if(pre->n == cur){
            p = p->n;
        }else{
            cur->n = pre->n;
            pre->n = cur;
            p->n = n;
        }
        cur = n;
    }
    h = dummy->n;
    free(dummy);
    return h;
}

void main(){
    int val[] = {3,6,2,1,5,4,2,4};
    int len = sizeof(val)/sizeof(val[0]);

    nod *n = init(len,val);
    nod *n2 = init(len,val);
    printf("original data : 
");
    print_n(n);

    printf("sorted data : 
");
    nod *sn2 = insert_sort3(n2);
    print_n(sn2);
}

输出：

root@ubuntu:~/cdir# gcc insert_sort_linkedlist.c -o insert_sort_linkedlist.bin -g
root@ubuntu:~/cdir# ./insert_sort_linkedlist.bin 
original data : 
3(0) -> 6(1) -> 2(2) -> 1(3) -> 5(4) -> 4(5) -> 2(6) -> 4(7) -> 
sorted data : 
1(3) -> 2(2) -> 2(6) -> 3(0) -> 4(5) -> 4(7) -> 5(4) -> 6(1) -> 

通过括号内给的 val 值，可以看到 ，相同key的 2 和 4，排序后，相对位置没有发生改变,保证了稳定性

睡觉