```
class Solution:
# @param A a list of integers
# @return nothing, sort in place
def sortColors(self, A):
last_r, last_w = -1, -1
for i in xrange(len(A)):
if A[i] == 0:
if i > last_r + 1:
A[i], A[last_r + 1] = A[last_r + 1], A[i]
last_r += 1
if A[i] == 1:
if last_w < last_r:
last_w = last_r
if i > last_w + 1:
A[i], A[last_w + 1] = A[last_w + 1], A[i]
last_w += 1
```