I share a solution using dict

```
def getHint(self, secret, guess):
sDic = {'0':0,'1':0,'2':0,'3':0,'4':0,'5':0,'6':0,'7':0,'8':0,'9':0}
gDic = {'0':0,'1':0,'2':0,'3':0,'4':0,'5':0,'6':0,'7':0,'8':0,'9':0}
length = len(secret)
bulls, cows = 0, 0
# count the number of 0-9 in secret and guess, and calculate bulls
for i in range(length):
s, g = secret[i], guess[i]
sDic[s] += 1
gDic[g] += 1
if s == g:
bulls += 1
# calculate cows, add up the min of sDic and gDic, then minus bulls
for k in sDic.keys():
cows += min(sDic[k], gDic[k])
cows -= bulls
# return result
return "%dA%dB" % (bulls,cows)
```