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, 2
is written as II
in Roman numeral, just two one's added together. 12
is written as XII
, which is simply X + II
. The number 27
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 beforeV
(5) andX
(10) to make 4 and 9. -
X
can be placed beforeL
(50) andC
(100) to make 40 and 90. -
C
can be placed beforeD
(500) andM
(1000) to make 400 and 900.
Given an integer, convert it to a roman numeral.
Example 1:
Input: num = 3
Output: "III"
Explanation: 3 is represented as 3 ones.
Example 2:
Input: num = 58
Output: "LVIII"
Explanation: L = 50, V = 5, III = 3.
Example 3:
Input: num = 1994
Output: "MCMXCIV"
Explanation: M = 1000, CM = 900, XC = 90 and IV = 4.
Constraints:
-
1 <= num <= 3999
SOLUTION:
class Solution:
def intToRoman(self, num: int) -> str:
sym = {
1: "I",
5: "V",
10: "X",
50: "L",
100: "C",
500: "D",
1000: "M"
}
keys = list(sym.keys())
k = len(keys)
vals = []
i = 1
while num > 0:
curr = num % (10 ** i)
vals.insert(0, curr)
num -= curr
i += 1
print(vals)
op = ""
curr = 0
while curr < len(vals):
v = vals[curr]
if v in sym:
op += sym[v]
else:
found = False
for i in range(k):
for j in range(i + 1, k):
if v == keys[j] - keys[i]:
found = True
op += sym[keys[i]] + sym[keys[j]]
break
if not found:
for key in keys[::-1]:
if v > key:
op += sym[key] * (v // key)
vals.insert(curr + 1, v % key)
break
curr += 1
return op
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