小黑南京归来，参加部里的公务员培训，有点儿社死认识了好多小伙伴的leetcode之旅13. 罗马数字转整数

小黑代码

class Solution:def romanToInt(self, s: str) -> int:chars = ['M', 'CM', 'D', 'CD', 'C', 'XC', 'L', 'XL', 'X', 'IX', 'V', 'IV','I']nums = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1]map_ = dict((k, v) for k,v in zip(chars, nums))# 字符串长度n = len(s)# 结果变量res = 0# 开始循环i = 0while i < n:# 判断两个字符if i+1 < n and s[i:i+2] in map_:# print(s[i:i+2], ':', map_[s[i:i+2]])res += map_[s[i:i+2]]i += 2else:res += map_[s[i]]# print(s[i], ':', map_[s[i]])i += 1return res

罗马数字性质

class Solution:def romanToInt(self, s: str) -> int:chars = ['M', 'D', 'C', 'L', 'X', 'V','I']nums = [1000, 500, 100, 50, 10, 5, 1]map_ = dict((k, v) for k,v in zip(chars, nums))# 字符串长度n = len(s)# 结果变量res = 0# 开始循环i = 0pre_num = map_[s[i]]for i in range(n):cur_num = map_[s[i]]if pre_num < cur_num:# print('-', pre_num)res -= 2*pre_numres += cur_num# print('+', cur_num)pre_num = cur_numreturn res