学习大神思路然后再码一遍 def cal_24(s, res): if len(s) == 1: return s[0] == res for i in range(len(s)): mid = s[i] rest = s[:i] + s[i+1:] if cal_24(rest, res + mid) \ or cal_24(rest, res - mid) \ or cal_24(rest, res / mid) \ or cal_24(rest, res * m...