排  序

排序方法：

（1）插入排序

（2）交换排序

（3）选择排序

（4）归并排序

（5）基数排序

培训详细：

以插入排序、交换排序为例，对排序思想进行具体分析，以及对代码的解读。争取让大家读懂并且理解具体代码的作用。

插入排序

基本思想：每一趟将一个待排序的记录，按其关键字的大小插入到已经排好序的一组记录的适当位置上，直到所有待排序记录全部插入为止。

1.     直接插入排序

?  基本代码：

*        void insert_order(int a[], intn, int key)

*        {

*           int i;

*           for (i = n-1; i >= 0; i--)

*           {

*                    if (key < a[i])

*                             a[i+1] = a[i];

*                    else

*                             break;

*           }

*           a[i+1] = key;

*        }

*        void sort_insert(int a[], intn)

*        {

*           int i;

*           for (i = 1; i < n; i++)

*                    insert_order(a, i, a[i]);

*        }

2.     折半插入排序

?  基本代码：

*        void insert_order(int a[], intn, int key)

*        {

*           int m;

*           int i;

*           int low = 0;

*           int high = n - 1;

*           while(low <= high)

*           {

*                    m = (low+high)/2;

*                    if(key < a[m])

*                             high = m-1;

*                    else

*                             low = m+1;

*           }

*           for (i = n-1; i > high; i--)

*                    a[i+1] = a[i];

*           a[high+1] = key;

*        }

*        void sort_insert(int a[], intn)

*        {

*               int i;

*               for (i = 1; i < n; i++)

*                             insert_order(a,i, a[i]);

*        }

交换排序：

基本思想：两两比较待排序记录的关键字，一旦发现两个记录不满足次序要求时则进行排序，知道整个序列全部满足要求为止。

1.     冒泡排序bubble_sort

?  常规代码：

*        void bubble_sort(int a[], intn)

*        {

*           int i;

*           int j;

*           int temp;

*           for (i = 0; i<n; i++)

*           {

*                    for (j = 0; j <n-i-1; j++)

*                    {

*                             if (a[j] > a[j+1])

*                             {

*                                       temp = a[j];

*                                       a[j] = a[j+1];

*                                       a[j+1] = temp;

*                             }

*                    }

*           }

*        }

?  改进版冒泡：

*        void bubble_sort(int a[], intn)

*        {

*           int i;    int j;   int flag = 1;    int temp;

*           for (i = 0; i<n&&flag; i++)

*           {

*               flag = 0;

*             //flag置为0，如果本趟排序没有发生变化，则不会执行下趟排序

*               for (j = 0; j < n-i-1; j++)

*               {

*                             if (a[j]> a[j+1])

*                             {

*                                      flag= 1;   

*                       temp = a[j]; a[j] = a[j+1]; a[j+1] = temp;

*                             }

*                }

*            }

*        }

2.     快速排序

?  方法一：

*        int quickSort(int a[], int p,int r)

*        {

*            int i, j;   int q;    int temp;    i = p-1;

*            if(p > r)        return 0;

*            for(j = p; j < r; j++)

*            {

*                if(a[j] < a[r])

*                {

*                    temp = a[j];   a[j] = a[i+1];     a[i+1] = temp; 

*                    i++;

*                }

*            }

*            temp = a[i+1];    a[i+1] = a[r];    a[r] = temp;

*            q = i+1;

*            quickSort(a, p, q-1);

*            quickSort(a, q+1, r);

*        }

?  方法二：

*        int Partition(int a[], int low,int high)

*        {

*           int pivotkey;

*         

*           pivotkey = a[low];

*           while (low < high)

*           {

*                    while (low < high && pivotkey <= a[high])

*                    {

*                             --high;

*                    }

*                    a[low] = a[high];

*         

*                    while (low < high && pivotkey >= a[low])

*                    {

*                             ++low;

*                    }

*                    a[high] = a[low];

*           }

*         

*           a[low] = pivotkey;

*           return low;                      //返回关键字的坐标

*        }

*         

*        void quickSort(int a[], intlow, int high)

*        {

*           int pivotloc;

*         

*           if (low < high)

*           {

*                    pivotloc = Partition(a, low, high);   //接收关键字的位置

*                    quickSort(a, low, pivotloc-1);

*                    quickSort(a, pivotloc+1, high);

*           }

*        }

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排序

原文：http://blog.csdn.net/mullerwch/article/details/21773675