鏈表排序

       對無序的單鏈表，看起來好簡單的樣子，但是竟然沒有看到過、也沒有想到過這個問題，直到今天的一道面試題......矮油，一心想要冒泡，但是以我的臨場反應速度...寫正確纔不正常呢！結果冒泡未成功，倒是冒了很多汗，筆試現場很火爆啊很怪異有木有！看來鄙人對電腦和編譯環境的依賴程度嚴重啊！好嘛，馬後炮嘛，貢上我的測試代碼嘛

 

       排序函數：

link_node *sort_linklist(link_node *head)
{

    int flag = 1;
    link_node *p = NULL;

    assert(NULL != head->next);
    p = head->next;

    while(flag)
    {
        flag = 0;
        p = head->next;
        while(NULL != p)
        {
            if(NULL != p->next && (p->data > p->next->data))
            {
                int temp = p->data;
                p->data = p->next->data;
                p->next->data = temp;
                flag = 1;
            }
            p = p->next;
        }
    }
    return head;
}

       測試代碼：

#include <iostream>
#include <assert.h>

using namespace std;

const int N = 8;

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

int main()
{
    link_node *sort_linklist(link_node *head);

    int set[N] = {1,9,3,2,8,5,18,15};
    int i = 0;

    link_node *head = new link_node;
    assert(NULL != head);
    link_node *p = NULL,*q = NULL;
    head->next = p;

    head->data = N;
    while(i < N)
    {
        q = new link_node;
        q->data = set[i];
        if(NULL == p)
        {
            p = q;
            head->next = q;
        }
        else
        {
            p->next = q;
            p = q;
        }
        ++i;
    }
    p->next = NULL;

    cout << "The linklist to be sorted is:" << endl;
    p = head->next;
    while(NULL != p)
    {
        cout << p->data << '\t';
        p = p->next;
    }
    cout << endl;
    cout << "head = " << head << endl << "head->data = " << head->data << endl;

    sort_linklist(head);

    cout << "The sorted linklist is:" << endl;
    p = head->next;
    while(NULL != p)
    {
        cout << p->data << '\t';
        p = p->next;
    }
    cout << endl;

    delete head;

    return 0;
}

       顯然，我自己都看出來了，冒了多餘的泡：每一趟都要遍歷完整個鏈表，尼瑪，這囉嗦程度！怎樣才能不冒一個多餘的泡呢？