"""Leetcode 12. Integer to Roman
Medium

URL: https://leetcode.com/problems/integer-to-roman/

Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M.

Symbol       Value
I             1
V             5
X             10
L             50
C             100
D             500
M             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 an integer, convert it to a roman numeral. Input is guaranteed to be within
the range from 1 to 3999.

Example 1:
Input: 3
Output: "III"

Example 2:
Input: 4
Output: "IV"

Example 3:
Input: 9
Output: "IX"

Example 4:
Input: 58
Output: "LVIII"
Explanation: L = 50, V = 5, III = 3.

Example 5:
Input: 1994
Output: "MCMXCIV"
Explanation: M = 1000, CM = 900, XC = 90 and IV = 4.
"""

class Solution(object):
    def intToRoman(self, num):
        """
        :type num: int
        :rtype: str
        """
        pass


def main():
    pass


if __name__ == '__main__':
    main()

"""Leetcode 12. Integer to Roman
Medium

URL: https://leetcode.com/problems/integer-to-roman/

Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M.

Symbol       Value
I             1
V             5
X             10
L             50
C             100
D             500
M             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 an integer, convert it to a roman numeral. Input is guaranteed to be within
the range from 1 to 3999.

Example 1:
Input: 3
Output: "III"

Example 2:
Input: 4
Output: "IV"

Example 3:
Input: 9
Output: "IX"

Example 4:
Input: 58
Output: "LVIII"
Explanation: L = 50, V = 5, III = 3.

Example 5:
Input: 1994
Output: "MCMXCIV"
Explanation: M = 1000, CM = 900, XC = 90 and IV = 4.
"""

class SolutionIntRomanList(object):
    def intToRoman(self, num):
        """
        :type num: int
        :rtype: str
        """
        # Use "decreasing" integer-roman list.
        int_romans = [(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')]

        # Iteratively substract by integer, and store Roman into list.
        res = []

        for i, r in int_romans:
            while num >= i:
                res.append(r)
                num -= i

            # If no num, join into a Roman string.
            if not num:
                return ''.join(res)


def main():
    # Output: "III"
    num = 3
    print SolutionIntRomanList().intToRoman(num)

    # Output: "IV"
    num = 4
    print SolutionIntRomanList().intToRoman(num)

    # Output: "IX"
    num = 9
    print SolutionIntRomanList().intToRoman(num)

    # Output: "LVIII"
    num = 58
    print SolutionIntRomanList().intToRoman(num)

    # Output: "MCMXCIV"
    num = 1994
    print SolutionIntRomanList().intToRoman(num)


if __name__ == '__main__':
    main()

Complete int roman list sol