总结并编写了部分常用的排序算法，包括前向、后向冒泡排序、简单选择排序、直接插入排序、希尔排序、堆排序、并归排序和快速排序。
具体的原理请参考《大话数据结构》。
#include<stdio.h>
#include<malloc.h>
//从前向后冒泡 =======================================================
void bubble(int arr[], int n)
{
for (int i = 0; i < n - 1; i++)
{
for (int j = 0; j < n - 1 - i; j++)
{
if (arr[j] > arr[j + 1])
{
int temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
}
}
//从后向前冒泡
void bubble2(int arr[], int n)
{
for (int i = 0; i < n - 1; i++)
{
for (int j = n - 1; j > i; j--)
{
if (arr[j - 1] > arr[j])
{
int temp = arr[j];
arr[j] = arr[j - 1];
arr[j - 1] = temp;
}
}
}
}
//选择排序 =======================================================
void selectsort(int arr[], int n)
{
for (int i = 0; i < n ; i++)
{
int index = i;
for (int j = i + 1; j < n; j++)
{
if (arr[index] > arr[j])
index = j;
}
if (i != index)
{
int temp = arr[i];
arr[i] = arr[index];
arr[index] = temp;
}
}
}
//插入排序 =======================================================
void insertionsort(int arr[], int n)
{
for (int i = 1; i < n; i++)
{
int temp = arr[i];
while (i >= 0 && arr[i - 1] > temp)
{
arr[i] = arr[i - 1];
i--;
}
arr[i] = temp;
}
}
//希尔排序 =======================================================
void shellsort(int arr[], int n)
{
int gap = n;
int temp;
int i, j;
do
{
gap = gap / 2;
for (i = gap; i < n; i++)
{
if (arr[i] < arr[i - gap])
{
temp = arr[i];
for (j = i - gap; j >= 0 && temp < arr[j]; j -= gap)
arr[j + gap] = arr[j];
arr[j + gap] = temp;
}
}
} while (gap > 1);
}
//堆排序 =======================================================
void heapadjust(int arr[], int s, int m)
{
int j;
int temp = arr[s];
for (j = (2*s)+1; j < m; j *= 2)
{
if (j < m && arr[j] < arr[j + 1])
j++;
if (temp > arr[j])
break;
arr[s] = arr[j];
s = j;
}
arr[s] = temp;
}
void heapsort(int arr[], int n)
{
int i;
for (i = (n/2)-1; i >= 0; i--)
heapadjust(arr, i, n);
for (i = 0; i < n; i++)
{
int temp = arr[0];
arr[0] = arr[n-1-i];
arr[n-1-i] = temp;
heapadjust(arr, 0, n-1-i-1);
}
}
//归并排序
void merge(int arr[], int start, int mid, int end)
{
int* result = (int*)malloc((end + 1) * sizeof(int));
int k = 0;
int i = start;
int j = mid + 1;
while (i <= mid && j <= end) {
if (arr[i] < arr[j]) {
result[k++] = arr[i++];
}
else {
result[k++] = arr[j++];
}
}
if (i == mid + 1) {
while (j <= end)
result[k++] = arr[j++];
}
if (j == end + 1) {
while (i <= mid)
result[k++] = arr[i++];
}
for (j = 0, i = start; j < k; i++, j++) {
arr[i] = result[j];
}
free(result);
}
void mergeSort(int arr[], int start, int end)
{
if (start >= end)
return;
int mid = (start + end) / 2;
mergeSort(arr, start, mid);
mergeSort(arr, mid + 1, end);
merge(arr, start, mid, end);
}
//快速排序 =======================================================
int fun(int arr[], int low, int high)
{
int key;
key = arr[low];
while (low < high)
{
while (low < high && arr[high] >= key)
high--;
if (low < high)
arr[low++] = arr[high];
while (low < high && arr[low] <= key)
low++;
if (low < high)
arr[high--] = arr[low];
}
arr[low] = key;
return low;
}
void quicksort(int arr[], int start, int end)
{
int pos;
if (start < end)
{
pos = fun(arr, start, end);
quicksort(arr, start, pos - 1);
quicksort(arr, pos + 1, end);
}
}
//=======================================================
//=======================================================
int main()
{
int arr[] = {
9,5,1,4,0,7,2,6,8,3 };
//冒泡排序
//bubble(arr, 10);
//bubble2(arr, 10);
//选择排序
//selectsort(arr, 10);
//插入排序
//insertionsort(arr, 10);
//希尔排序
//shellsort(arr, 10);
//堆排序
//heapsort(arr, 10);
//归并排序
//mergeSort(arr, 0, 9);
//快速排序
quicksort(arr, 0, 9);
for (int i = 0; i < 10; i++)
printf("%d ", arr[i]);
return 0;
}