三色球，相同颜色不相邻，排列个数。
image.png
def fun(l1_,l2_):
l1 = [[i[0],i[1]] for i in l1_]
l2 = [i for i in l2_]
global result
if l1[0][1] == 0 and l1[1][1] == 0 and l1[2][1] == 0:
result += 1
print(l2)
return 1
for i in range(3):
tu = l1[i]
if l1[i][1]!=0:
if len(l2) == 0:
l2.append(l1[i][0])
l1[i][1] -= 1
fun(l1, l2)
elif l2[-1] != l1[i][0]:
l2.append(l1[i][0])
l1[i][1] -= 1
fun(l1, l2)
else:
continue
nPQR = input()
np = int(nPQR.split(" ")[0])
nq = int(nPQR.split(" ")[1])
nr = int(nPQR.split(" ")[2])
l1= [["P" , np], ["Q" , nq], ["R" , nr] ]
l2 = []
result = 0
fun(l1,l2)
print(result)
