排序算法总结2

归并排序：

void merge(int *a,int *b ,int left,int right){    int l = left;    int r = right+1;    int m = (left+right)/2;    int k = m+1;    int i = left;    while (l<(m+1)&&k<r)    {        if (a[l]<a[k])        {            b[i] = a[l];            i++;            l++;        }        else        {            b[i] = a[k];            i++;            k++;        }    }    if (k>=r)    {        while (l<(m+1))        {            b[i] = a[l];            i++;            l++;        }    }    else    {        while (k<r)        {            b[i] = a[k];            i++;            k++;        }    }    for (int i = left;i<=right;i++)    {        a[i] = b[i];    }}void merge_sort(int * a,int * b,int left,int right){    if (left < right)    {        int middle = (left+right)/2;        merge_sort(a,b,left,middle);        merge_sort(a,b,middle+1,right);        merge(a,b,left,right);    }}int main(){    int a[10] = {9,2,8,3,5,7,6,1,4,10};    int b[10]={0};    merge_sort(a,b,0,9);    for (int i=0;i<10;i++)    {        cout<<a[i]<<" ";    }    return 0;}

平均时间复杂度：nlogn

额外空间：n

稳定性：稳定

比较操作的次数介于(nlogn) / 2和nlogn - n + 1