InputIterator RandomSelect(InputIterator begin, InputIterator end, InputIterator I)
{
InputIterator endElemt = end;
InputIterator beginElemt = begin;
--endElemt;
if (beginElemt == endElemt)
return beginElemt;
InputIterator pos = RandomizedPartions(begin, end);
if (pos > I){
return RandomSelect(begin, pos, I);
}else if (pos < I){
return RandomSelect(++pos, end, I);
}
return pos;
}
wgttype RandomSelect(wgttype *a, int start, int end, int i)
{
int q,k,j;
if (start==end)
return a[start];
q=RandomPartition(a,start,end);
// printf("After rand partition, q:%d, end:%d\n",q,end);
/* for(j=start;j<=end;j++)
printf("%f,",a[j]);
printf("\n");
abort();
*/
k=q-start+1;
if (k==i)
return a[q];
if (i < k )
return RandomSelect(a,start,q-1,i);
else
return RandomSelect(a,q+1,end,i-k);
}
