Dutch Flag problem

Dutch flag is a notable problem wherein you have a array representing three colors . Red(R), Green(G) and Blue(B) which needs to be sorted with Reds coming first followed by Green and then Blue. This is achieved by lumoto partitioning scheme.

	arr = ['G','B','R','G','B','G','R']
	ridx=0
	bidx=len(arr)-1
	i=0
	while(i<bidx):
	if(arr[i] == 'R'):
	arr[i],arr[ridx] = arr[ridx],arr[i]
	ridx += 1
	i = i+1
	elif (arr[i] == 'B'):
	arr[i],arr[bidx] = arr[bidx], arr[i]
	bidx -= 1
	else:
	i=i+1
	print(arr)

view raw dutchflag.py hosted with ❤ by GitHub