Given an integer value in the range [1, 3999], convert it to its Roman numeral representation as a string. Roman numerals are formed by combining the following symbols and values: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. Subtractive notation is used for 4 (IV), 9 (IX), 40 (XL), 90 (XC), 400 (CD), and 900 (CM). Only powers of 10 (I, X, C, M) can be repeated up to three times in succession. Return the Roman numeral string corresponding to the input integer.
Example 1
Input: integer_value=2421
Output: MMCDXXI
Explanation: 2000 = MM, 400 = CD, 20 = XX, 1 = I
Example 2
Input: integer_value=83
Output: LXXXIII
Explanation: 50 = L, 30 = XXX, 3 = III
Example 3
Input: integer_value=1459
Output: MCDLIX
Explanation: 1000 = M, 400 = CD, 50 = L, 9 = IX
Constraints
Case 1
Input: integer_value=2768
Expected: 'MMDCCLXVIII'
Case 2
Input: integer_value=3999
Expected: 'MMMCMXCIX'
Case 3
Input: integer_value=120
Expected: 'CXX'
Case 4
Input: integer_value=7
Expected: 'VII'
Case 5
Input: integer_value=1111
Expected: 'MCXI'