描述
Given a roman numeral, convert it to an integer.
Input is guaranteed to be within the range from 1 to 3999
分析
比Integer to Roman简单多了，是加法规则还是减法规则很好判断。
代码
Python
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| class Solution(object):
def romanToInt(self, s):
"""
:type s: str
:rtype: int
"""
d = {
'M': 1000,
'D': 500,
'C': 100,
'L': 50,
'X': 10,
'V': 5,
'I': 1
}
n = len(s)
r = 0
for i in xrange(n):
a = d[s[i]]
if i < n - 1 and a < d[s[i + 1]]:
a = -a
r += a
return r
|