选择排序及其优化

#include<stdio.h>
#include<assert.h>

void swap(int *a, int *b)
{
int tmp = *a;
*a = *b;
*b = tmp;
}
void SelectSort(int *arr, int size)
{
int i = 0;
int j = 0;
int max = 0;
for (i = 0; i < size - 1 ; i++)
{
max = i;
for (j = i; j < size ; j++)   //j从i的地方开始
{
if (arr[max] < arr[j])
{
max = j;
}
}
if (max != i)                          //
SSwap(&arr[i], &arr[max]);
}
}
void SPrint(int *arr, int size)
{
int i = 0;
for (; i < size; i++)
{
printf("%d ", arr[i]);
}
printf("\n");
}

void SelectSortTest()
{
int arr[] = { 5, 1, 2, 3, 6, 7, 8, 9, 0 };
int size = sizeof(arr) / sizeof(arr[0]);
SPrint(arr, size);

SelectSort2(arr, size);
SPrint(arr, size);
}

void SelectSort2(int *arr, int n)
{
assert(arr);
int left = 0;
int right = n - 1;
while (left < right)
{
int min = left;
int max = right;
for (int i = left; i <= right; i++)
{
if (arr[i] < arr[min])
min = i;
if (arr[i] > arr[max])
max = i;
}

swap(&arr[max], &arr[right]);

if (min == right)
{
min = max;
}//注释见下图
swap(&arr[min], &arr[left]);
left++;
right--;
}
}