方式1、將快速排序分爲查找函數和排序函數;
#include <stdio.h>
/*查找函數*/
int Findpow(int *arr, int low, int high)
{
int flag=arr[low]; //將需要查找位置的第一個數字賦值給flag;
while (low < high)//邊界條件;
{
while ((low<high) && (arr[high] >= flag))//當高位大於等於flag標誌位時,應該將高位<<右移;
{
--high;//右移;
}
if (low < high)
{
arr[low] = arr[high];//當高位小於flag時,賦值給低位;
}
while ((low<high) && (arr[low] <= flag))//當低位小於等於flag標誌位時,應該將低位>>左移;
{
++low;//左移;
}
if (low < high)
{
arr[high] = arr[low];//當低位大於flag時,賦值給高位;
}
}
arr[low] = flag;//當low和high重合時,位置找到,將需要查找的數放進位置。
return low;//將這個位置返回給排序函數;
}
/*排序函數【遞歸實現】*/
void QiuckSort(int *arr, int low, int high)
{
int pow=0;//設置位置標誌;
if (low<high)
{
pow = Findpow(arr,low, high);//該位置將原來的線性數據分成兩半;
QiuckSort(arr, low, pow-1);//再將左邊的數據查找切分;
QiuckSort(arr, pow+1,high);//再將右邊的數據查找切分;
}
}
/*測試主函數*/
int main()
{
int a[] = { 4, 1, -2, 56, 22, 4, 7, 52, 4, 8, 6, 2 ,-5};
int num = sizeof(a) / sizeof(int);
QiuckSort(a, 0, num-1);
for (int i = 0; i < num; i++)
{
printf("%d ",a[i]);
}
getchar();
return 0;
}
方式2、將快速排序合併爲一個函數;
[合併時,主要是注意變量的改變問題]
#include <stdio.h>
/*快速排序函數【完整功能】*/
void QiuckSort(int *arr, int low, int high)
{
if (low<high)
{
int pow;
int flag;
int nlow = low, nhigh = high;//在該函數內low和high屬於全局變量,所以應該讓局部變量改變,全局變量不變。
flag = arr[low];
while (nlow < nhigh)
{
while ((nlow<nhigh) && (arr[nhigh] >= flag))
{
--nhigh;
}
if (nlow<nhigh)
{
arr[nlow] = arr[nhigh];
}
while ((nlow<nhigh) && (arr[nlow] <= flag))
{
++nlow;
}
if (nlow < nhigh)
{
arr[nhigh] = arr[nlow];
}
}
arr[nlow] = flag;
pow = nlow;
QiuckSort(arr, low, pow - 1);
QiuckSort(arr, pow + 1, high);
}
}
/*測試主函數*/
int main()
{
int a[] = { 4, 1, -2, 56, 22, 4, 7, 52, 4, 8, 6, 2 ,-5};
int num = sizeof(a) / sizeof(int);
QiuckSort(a, 0, num-1);
for (int i = 0; i < num; i++)
{
printf("%d ",a[i]);
}
getchar();
return 0;
}