Find the kth largest element in an unsorted array.

gistfile1.py

def findKth(A, k):
  if k > len(A) or k < 1:
    raise Exception("Invalid Parameters.")
  i = 0
  while i < k:
    imax = i
    j = i + 1
    while j < len(A):
      if A[imax] < A[j]:
        imax = j
      if imax != i:
        A[imax], A[i] = A[i], A[imax]
      j += 1
    i += 1
  return A[-1]