。。几种排序的时间比较

#include<stdio.h>
#include<string.h>
#include<time.h>
#include<algorithm>
using namespace std;

int n = 50000;

void select(int b[])
{
    for (int i = 1; i <n; i++)
        for (int j = i + 1; j <= n; j++)
            if (b[i] > b[j]) swap(b[i], b[j]);
} 

void bubble(int b[])
{
    for (int i = 1; i < n; i ++)
        for (int j = 1; j < n; j ++)
            if (b[j] > b[j + 1]) swap(b[j], b[j + 1]);    
}

void quick(int b[], int l, int r)
{
    int i = l, j = r, x, y;
    x = b[(l + r) / 2];
    while (i <= j)
    {
        while (b[i] < x) i++;
        while (x < b[j]) j--;
        if (i <= j)
        {
            swap(b[i], b[j]);
            i++; j--;
        }
    }
    if (i < r) quick(b, i, r);
    if (l < j) quick(b, l, j);
}

int c[1000005];
void merge(int b[], int l, int r, int mid)
{
    for (int i = l; i <= r; i++) c[i] = b[i];
    int x1 = l, x2 = mid + 1;
    for (int i = l; i <= r; i++)
    {
        if (x1 > mid) b[i] = c[x2++];
        else if (x2 > r) b[i] = c[x1++];
        else if (c[x1] < c[x2]) b[i] = c[x1++];
        else b[i] = c[x2++];
    }
}
void mergesort(int b[], int l, int r)
{
    int mid = (l + r) / 2;
    if (l >= r) return;
    mergesort(b, l, mid);
    mergesort(b, mid + 1, r);
    merge(b, l, r, mid);
}

void insert(int b[])
{
    for (int i = 2; i <= n; i++)
    {
        int j = i;
        while (j > 1 && b[j] < b[j - 1]) 
        {
            swap(b[j], b[j - 1]);
            j--;
        }
    }
}

void heap(int b[], int i, int size)
{
    int child;
    for (; 2 * i <= size; i = child)
    {
        child = 2 * i;
        if (child < size && b[child + 1] > b[child]) child++;
        if (b[i] < b[child]) swap(b[i], b[child]);
        else break;
    }
}
void heapsort(int b[])
{
    for (int i = n / 2; i >= 1; i--)
        heap(b, i, n);
    for (int i = n; i > 1; i--)
    {
        swap(b[i], b[1]);
        heap(b, 1, i - 1);
    }
}

int a[1000005], b[1000005];
int main()
{
    srand(time(0));
    for (int i = 1; i <= n; i++) a[i] = rand();
    clock_t begin, duration;
     
    for (int i = 1; i <= n; i++) b[i] = a[i];
    begin = clock();
    select(b);
    duration = clock() - begin;
//    for (int i = 1; i <= n; i++) printf("%d ",b[i]); printf("\n");
    printf("select sort = %dms\n\n",duration*1000/CLOCKS_PER_SEC);
    
    for (int i = 1; i <= n; i++) b[i] = a[i];
    begin = clock();
    bubble(b);
    duration = clock() - begin;
//    for (int i = 1; i <= n; i++) printf("%d ",b[i]); printf("\n");
    printf("bubble sort = %dms\n\n",duration*1000/CLOCKS_PER_SEC);
    
    for (int i = 1; i <= n; i++) b[i] = a[i];
    begin = clock();
    quick(b, 1, n);
    duration = clock() - begin;
//    for (int i = 1; i <= n; i++) printf("%d ",b[i]); printf("\n");
    printf("quick sort = %dms\n\n",duration*1000/CLOCKS_PER_SEC);
    
    for (int i = 1; i <= n; i++) b[i] = a[i];
    begin = clock();
    mergesort(b, 1, n);
    duration = clock() - begin;
//    for (int i = 1; i <= n; i++) printf("%d ",b[i]); printf("\n");
    printf("merge sort = %dms\n\n",duration*1000/CLOCKS_PER_SEC);
    
    for (int i = 1; i <= n; i++) b[i] = a[i];
    begin = clock();
    insert(b);
    duration = clock() - begin;
//    for (int i = 1; i <= n; i++) printf("%d ",b[i]); printf("\n");
    printf("insert sort = %dms\n\n",duration*1000/CLOCKS_PER_SEC);
    
    for (int i = 1; i <= n; i++) b[i] = a[i];
    begin = clock();
    heapsort(b);
    duration = clock() - begin;
//    for (int i = 1; i <= n; i++) printf("%d ",b[i]); printf("\n");
    printf("heap sort = %dms\n\n",duration*1000/CLOCKS_PER_SEC);
}