romanEquations

Being an avid student, Jim loves to read books for his Roman classes such as those by Dante and Cicero. One day, he came across a huge string of Roman numerals and realized that it made no sense. Since Jim also loves misteries, he figured that the string must contain a hidden equation.

Help Jim figure out what equation is hidden in the given RomanNumerals. Only the following operators can be used:

1. exactly one = sign;
2. exactly one of the operators +, -, *, /, or % to the left of =.

Here are all valid Roman Numerals:

I = 1
V = 5
X = 10
L = 50
C = 100
D = 500
M = 1000

Anything above M will not be used in this challenge.

Make sure you understand how Roman numerals work, i.e.

IV = 4
IX = 9
etc.

Given RomanNumerals, insert valid operators so that the obtained equation makes sense. If no answer can be found, return "not possible" instead.

Example

• For RomanNumerals = "MXIIICCCLXMCCCLXXIII", the output should be RomanEquations(RomanNumerals) = "MXIII+CCCLX=MCCCLXXIII", because 1013 + 360 = 1373.

Input/Output

• [execution time limit] 0.5 seconds

• [input] string RomanNumerals

  The sequence of Roman numerals.

• [output] string

  It’s guaranteed that only one answer exists.

  A valid equation written in Roman Numerals, or "not possible" if it’s impossible to find one.