经典排序——归并、快排递归与非递归实现与冒泡排序

#include <iostream>
#include <cstdlib>
#include <ctime>
#include <cstdio>
#include <stack>
using namespace std;

void merge(int a[],int b[],int l,int mid,int r){
int i = l, j = mid + 1;
int k = 0;
while(i <= mid && j <= r){
if(a[i] <= a[j])
b[k++] = a[i++];
else
b[k++] = a[j++];
}
while(i <= mid) b[k++] = a[i++];
while(j <= r) b[k++] = a[j++];
for(i = 0 ; i < k; i ++)
a[i+l] = b[i];
}

void mergesort_recursive(int a[],int b[],int l,int r){
if(l < r){
int mid = (l + r) >> 1;
mergesort_recursive(a,b,l,mid);
mergesort_recursive(a,b,mid+1,r);
merge(a,b,l,mid,r);
}
}

void merge2(int a[],int b[],int l,int mid,int r){
int i = l, j = mid + 1;
int k = l;
while(i <= mid && j <= r){
if(a[i] <= a[j])
b[k++] = a[i++];
else
b[k++] = a[j++];
}
while(i <= mid) b[k++] = a[i++];
while(j <= r) b[k++] = a[j++];
}

void mergepass(int a[],int b[],int s,int n){
int i = 0;
while(i <= n - 2*s){
merge2(a,b,i,i+s-1,i+2*s-1);
i += 2*s;
}
if(i + s < n)
merge2(a,b,i,i+s-1,n-1);
else
for(int j = i ; j < n ; j ++)
b[j] = a[j];
}

void mergesort_unrecursive(int a[],int n){
int *b = new int
;
int s = 1;
while(s < n){
mergepass(a,b,s,n);
s += s;
mergepass(b,a,s,n);
s += s;
}
// for(int i = 0 ; i < n ; i ++)
//  printf("%d ",a[i]);
}

bool MergeSort1(int a[],int n){
int *b = new int
;
if(b == NULL)
return false;
mergesort_recursive(a,b,0,n-1);
//for(int i = 0 ; i < n ; i ++)
//  printf("%d ",a[i]);
// puts("");
delete b;
return true;
}

void swap(int &a,int &b){
int temp;
temp = a;a = b; b = temp;
}

int partition(int a[],int l,int r){
int m = ((r - l) >> 1) + l;
swap(a[m],a[r]);
int x = a[r];
int i = l - 1;
for(int j = l ; j < r ; j ++){
if(a[j] < x){
i ++;
swap(a[i],a[j]);
}
}
swap(a[i+1],a[r]);
return i + 1;
}

void qsort(int a[],int l,int r){
if(l < r){
int q = partition(a,l,r);
qsort(a,l,q-1);
qsort(a,q+1,r);
}
}

void qsort_recursive(int a[],int l,int r){
stack<int> st1;
stack<int> st2;
st1.push(l);
st2.push(r);
while(!st1.empty() && !st2.empty()){
int tleft = st1.top();
int tright = st2.top();
st1.pop(),st2.pop();
if(tleft >= tright) continue;
int q = partition(a,tleft,tright);
st1.push(tleft);st1.push(q+1);
st2.push(q-1);st2.push(tright);
}
}

void bubblesort(int a[],int n){
bool flag = true;
int k = n;
while(flag){
flag = false;
for(int j = 1; j < k ; j ++){
if(a[j - 1] > a[j]){
swap(a[j-1],a[j]);
flag = true;
}
}
k --;
}
}

int random(int n){
double ran = (double)(rand()/(double)RAND_MAX);
ran = ran * (n - 1) + 1.0;
return (int)ran;
}

int main()
{
srand((int)time(0));
double ans;
for(int n = 100 ; n <= 10000000 ; n *=10){
int *a = new int
;
for(int i = 0 ; i < n ; i ++)
a[i] = random(n*10);

clock_t start,finish;
start = clock();
bool res = MergeSort1(a,n);
finish = clock();
ans = (double)(finish - start) / CLOCKS_PER_SEC;
printf("数据量为%d时:\n",n);
printf("递归归并排序耗时：%.1fms\n",ans*1000);

for(int i = 0 ; i < n ; i ++)
a[i] = random(n*10);
start = clock();
mergesort_unrecursive(a,n);
finish = clock();
ans = (double)(finish - start) / CLOCKS_PER_SEC;
printf("非递归归并排序耗时：%.1fms\n",ans*1000);

for(int i = 0 ; i < n ; i ++)
a[i] = random(n*10);
start = clock();
qsort(a,0,n-1);
finish = clock();
ans = (double)(finish - start) / CLOCKS_PER_SEC;
printf("递归快速排序耗时：%.1fms\n",ans*1000);

for(int i = 0 ; i < n ; i ++)
a[i] = random(n*10);
start = clock();
qsort_recursive(a,0,n-1);
finish = clock();
ans = (double)(finish - start) / CLOCKS_PER_SEC;
printf("非递归快速排序耗时：%.1fms\n",ans*1000);

for(int i = 0 ; i < n ; i ++)
a[i] = random(n*10);
start = clock();
//bubblesort(a,n);
finish = clock();
ans = (double)(finish - start) / CLOCKS_PER_SEC;
printf("冒泡排序耗时：%.1fms\n",ans*1000);
printf("\n");
delete []a;
}
return 0;
}