Integer to Roman Leetcode Solution
In this tutorial, we are going to solve the Integer to Roman problem from leetcode in python.
Task:
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 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.
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
Solutions:
class Solution:
def intToRoman(self, num: int) -> str:
srt = ""
values = [1,4,5,9,10,40,50,90,100,400,500,900,1000]
symbols = ['I','IV','V','IX','X','XL','L','XC','C','CD','D','CM','M']
j = len(values) - 1
while num:
quo = num // values[j]
num %= values[j]
while quo:
srt += symbols[j]
quo -= 1
j -= 1
return srt
Steps:
step1: Firstly, we make an empty string as per the return type.
step2: Now, we make two lists initialising as integer values of roman symbols and the other list is roman symbols.
step3: then we loop till the given integer num.
step4: then, we integer divide the num with values[j] (as we are going from the last element of values) and store it in quo variable and changing the num to it's modulus with values[j].
step5: now we run a loop till quo variable and the respective symbol[j] in our empty string.
step6: then we update the j variable to move left to right in both the lists and after the while loop, return the string.
