[LeetCode][Python]Integer to Roman

# -*- coding: utf8 -*-
'''
__author__ = '[email protected]'
https://oj.leetcode.com/problems/integer-to-roman/
Integer to Roman

Given an integer, convert it to a roman numeral.

Input is guaranteed to be within the range from 1 to 3999.
===Comments by Dabay===
 google         ：
I - 1
V - 5
X - 10
L - 50
C - 100
D - 500
M - 1000
         4,40     。
  999   ，  900     CM，       CM，    900 99；     500 499.
            ，       ，        hash      ，            。
'''

class Solution:
    # @return a string
    def intToRoman(self, num):
        pairs = [
            (1000,"M"),
            (900,"CM"),
            (500,"D"),
            (400,"CD"),
            (100,"C"),
            (90,"XC"),
            (50,"L"),
            (40,"XL"),
            (10,"X"),
            (9,"IX"),
            (5,"V"),
            (4,"IV"),
            (1,"I")
        ]
        res = ""
        for (n, s) in pairs:
            while num >= n:
                res = res + s
                num = num - n
        return res


def main():
    s = Solution()
    print s.intToRoman(6)


if __name__ == "__main__":
    import time
    start = time.clock()
    main()
    print "%s sec" % (time.clock() - start)