algorithm/Sorts.cpp at master · cdle/algorithm · GitHub

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#include<iostream>
usingnamespacestd;

//归并排序
template<typename T>
voidmergeSort(T* arr,int e, int b = 1)
{
if(e!=b)
 {
int d = (e-b)/2;
mergeSort(arr, b+d, b);
mergeSort(arr, e, b+d+1);
if(arr[b+d-1]<arr[b+d])//优化
 {
 T* cp = new T[e-b+1];
copy(arr+(b--)-1, arr+e, cp);
 T* xp = cp;
 T* mp = cp + d;
 T* yp = mp + 1;
while(b<e){
 arr[b++] = (xp<=mp && *xp>*yp) ? *(xp++) : *(yp++);
 };
delete[] cp;
 }
 }
}

//自下而上的归并排序
template<typename T>
voidmergeSortUB(T* arr,int n)
{
for(int t =1; t<=n; t+=t)
 {
for(int r=0; r+t < n; r+=t+t)
 {
int b = r+1;
int e = min(r+t+t,n);
int d = t-1;
if(arr[b+d-1]<arr[b+d])
 {
 T* cp = new T[e-b+1];
copy(arr+(b--)-1, arr+e, cp);
 T* xp = cp;
 T* mp = cp + d;
 T* yp = mp + 1;
while(b<e){
 arr[b++] = (xp<=mp && *xp>*yp) ? *(xp++) : *(yp++);
 };
delete[] cp;
 }
 }
 }
}

//快速排序
template<typename T>
voidquickSort(T *arr,int n,int j=1)
{
if(n<=1)return;
int v = arr[j-1];
int q = j;
for(int i=0; i<n-1; i++)
 {
if(v<arr[q+i])
 {
swap(arr[j++],arr[q+i]);
 }
 }
swap(arr[q-1],arr[j-1]);
quickSort(arr,j-q,q);
quickSort(arr,n-j+q-1,j+1);
}

//双路快速排序
template<typename T>
voidquickSort2Ways(T *arr,int m,int n)
{
if(n-m==1)
 {
if(arr[m]<arr[n])
 {
swap(arr[m],arr[n]);
 }
 }elseif(n>m){
int i = m+1;
int j = n;
int v = arr[m];
while(true)
 {
while(arr[i++]>v);
while(arr[j--]<v);
if(i-1>j+1)break;
swap(arr[i-1],arr[j+1]);
 };
swap(arr[i-2],arr[m]);
quickSort2Ways(arr,m,i-3);
quickSort2Ways(arr,i-1,n);
 }
}

//三路快速排序
template<typename T>
voidquickSort3Ways(T *arr,int m,int n)
{
int l = m;
int p = m+1;
int r = n+1;
int v = arr[m];
while(p<r){
if(arr[p]>v){
swap(arr[l+1],arr[p]);
 l++;
 p++;
 }elseif(arr[p]==v){
 p++;
 }else{
swap(arr[p],arr[r-1]);
 r--;
 }
 }
if(l>m){
swap(arr[m],arr[l]);
quickSort3Ways(arr,m,l-1);
 }
if(r<n)quickSort3Ways(arr,r,n);
}

template<typename Item>
inlinevoidshiftDown(Item* arr,int n,int k)
{
int j = 2*k+1;
while(j<=n-1){
if(j+1<=n-1 && arr[j]<arr[j+1])j++;
if(arr[k]>=arr[j])break;
swap(arr[k], arr[j]);
 k = j;
 }
}

//堆排序
template<typename Item>
voidheapSort(Item* arr,int n)
{
int l = (n-2)/2;
for(int i=0; i<=l; i++)
 {
shiftDown(arr,n,i);
 }
for(int i=1; i<n; i++)
 {
swap(arr[0],arr[n-i]);
shiftDown(arr,n-i,0);
 }
}

intmain()
{
int arr[] = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20};
mergeSort(arr,20);
for (int i = 0; i < 20; i++)
 {
 cout << arr[i] << "";
 }
return0;
}