void fast_sort(T a[], int begin, int end)
{
//recursion exit
//when not a valid array, or begin > end or only 1 element (begin==end), we don't do anything, just return
if (!a || begin >= end) {
return;
}
//select the first item as axis, partition the array
T x = a[begin];
int i = begin, j= end;
while (i<j)
{
while(i<j && a[j]>=x)
j--;
if(i<j)
{
a[i]=a[j];
i++;
}
while (i<j && a[i]<x) {
i++;
}
if(i<j)
{
a[j]=a[i];
j--;
}
}
a[i]=x;
fast_sort(a, begin, i-1);
fast_sort(a, i+1, end);
}
void fast_sort(int arr[],int low,int high)
{
int keylocation;
if(low<high)
{
keylocation=find_key(arr,low,high);
fast_sort(arr,low,keylocation);
fast_sort(arr,keylocation+1,high);
}
}
void fast_sort(int a[], int left, int right)
{
if(left < right)
{
int i = left, j = right, tmp = a[left];
while(i<j)
{
while(i<j&&a[j]>=tmp)j--;
if(i<j)a[i++] = a[j];
while(i<j&&a[i]<tmp)i++;
if(i<j)a[j--] = a[i];
}
a[i] = tmp;
fast_sort(a,left,i-1);
fast_sort(a,i+1,right);
}
}
void
fast_sort(int *a, int start, int end) {
int i, j, key, temp;
if (start >= end) {
return;
}
key = a[start];
i = start;
j = end;
while (i<j) {
while (j>i) {
if (a[j] < key) break;
j--;
}
while (i<j) {
if (a[i] > key) break;
i++;
}
if (i != j) {
temp = a[i];
a[i] = a[j];
a[j] = temp;
}
}
a[start] = a[i];
a[i] = key;
fast_sort(a, start, i-1);
fast_sort(a, i+1, end);
my_print2(a, start, end);
}
void testSort()
{
int x[] = {7,3,4,8,8,5,1,2,4};
int a[9];
printArray(x,9);
memcpy(a,x,sizeof(int)*9);
cout<<"merge sort:"<<endl;
merge_sort(a, 0, 8);
printArray(a, 9);
memcpy(a,x,sizeof(int)*9);
cout<<"fast sort:"<<endl;
fast_sort(a, 0, 8);
printArray(a, 9);
memcpy(a,x,sizeof(int)*9);
cout<<"bubble sort:"<<endl;
bubble_sort(a, 9);
printArray(a, 9);
memcpy(a,x,sizeof(int)*9);
cout<<"select sort:"<<endl;
select_sort(a, 9);
printArray(a, 9);
memcpy(a,x,sizeof(int)*9);
cout<<"insert sort:"<<endl;
insert_sort(a, 9);
printArray(a, 9);
memcpy(a,x,sizeof(int)*9);
cout<<"count sort:"<<endl;
count_sort(a, 9);
printArray(a, 9);
}
void Qsort(int arr[],int length)
{
fast_sort(arr,0,length-1);
}
void mySort(int a[], int n)
{
assert(a && n>0);
fast_sort(a, 0, n-1);
}
void testFast_sort()
{
int a[] = {7,3,4,8,8,5,1,2,4};
fast_sort(a, 0, 8);
printArray(a, 9);
}
