int partion(int *x,int low,int high){   int temp=x[low];   int i=low;   int j=high+1;   while(true){     while(x[++i]<temp);     while(x[--j]>temp);     if(i>=j) break;     swap(x[i],x[j]);   }   x[low]=x[j];   x[j]=temp;   return j;}int quickpass(int *x,int low,int high){    if(low<high){        int p=partion(x,low,high);        quickpass(x,low,p-1);        quickpass(x,p+1,high);    }}

//求第k小的元素int mink(int *m,int low,int high,int k){    if(low==high) return m[low];    int f=partion(m,low,high);    //左边的元素的个数
    int lnum=f-low+1;    if(lnum>=k)       return mink(m,low,f,k);    else       return mink(m,f+1,high,k-lnum);}