Algorithm - Find k-th order element in a list （课堂笔记）

FindKthElement( unsortedList, k ):
// select pivot;
randomly select a pivot m in unsortedList;
// partition;
put all elements smaller than unsortedList[m] into L; all elems greater than unsorted[m] into R;
// compare L.length, R.length, k
if L.length<k:
FindKthElement(R, k-L.length):
else if L.length = k:
return unsortedList[L.length+1];
else if L.length>k:
FindKthElement(L, k);