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题目：
Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M.
Symbol ValueI 1V 5X 10L 50C 100D 500M 1000
For example, two is written as II in Roman numeral, just two one's added together. Twelve is written as, XII, which is simply X + II. The number twenty seven is written as XXVII, which is XX + V + II.
Roman numerals are usually written largest to smallest from left to right. However, the numeral for four is not IIII. Instead, the number four is written as IV. Because the one is before the five we subtract it making four. The same principle applies to the number nine, which is written as IX. There are six instances where subtraction is used:
I can be placed before V (5) and X (10) to make 4 and 9. X can be placed before L (50) and C (100) to make 40 and 90. C can be placed before D (500) and M (1000) to make 400 and 900.Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999.
Example 1:
Input: "III"Output: 3
Example 2:
Input: "IV"Output: 4
Example 3:
Input: "IX"Output: 9
Example 4:
Input: "LVIII"Output: 58Explanation: L = 50, V= 5, III = 3.
Example 5:
Input: "MCMXCIV"Output: 1994Explanation: M = 1000, CM = 900, XC = 90 and IV = 4.
解答一：
这是第二次的答案faster than 43%, 还凑合
class Solution: def romanToInt(self, s): """ :type s: str :rtype: int """ d1 = { 'I':1, 'V':5, 'X':10, 'L':50, 'C':100, 'D':500, 'M':1000 } length = len(s) result = 0 for i in range(length): if i == length-1: result += d1[s[i]] return result if d1[s[i]] 解答二：
这是第一次的解答，leetcode数据显示属于贼慢的那种faster than 2%，哭T_T
class Solution: def romanToInt(self, s): """ :type s: str :rtype: int """ d1 = { 'I':1, 'V':5, 'X':10, 'L':50, 'C':100, 'D':500, 'M':1000 } length = len(s) result = 0 for i in range(length): if i == length-1: result += d1[s[i]] return result if d1[s[i]]
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