Function to sort a binary list in linear time
def sort(A):
# count number of 0's
zeros = A.count(0)
# put 0's at the beginning
k = 0
while zeros:
A[k] = 0
zeros = zeros - 1
k = k + 1
# fill all remaining elements by 1
for k in range(k, len(A)):
A[k] = 1