504 Base 7

1. Description

Given an integer num, return a string of its base 7 representation.

 

constraints :

• \(-10^{7}\) <= num <= \(10^{7}\)

2. Algorithms

1. Start
2. Declare variable named sign initialized to 1.
3. If num is smaller than zero, assign -1 to sign.
4. Declare variable named digits initialized to empty list.
5. Repeat the steps until num == 0 :
   1. Append remainder of num divide 7 to digits.
   2. Update num as num mod 7.
6. If sign is -1, append "-" to digits.
7. Return reverse joined digits.
8. End

3. Codes

class Solution:
    def convertToBase7(self, num: int) -> str:
        sign = 1 
        if num < 0 : sign = -1 
        if num == 0 : return "0"
            
        num *= sign 
        digits = [] 
        
        while num > 0 : 
            digits.append(str(num % 7))
            num //= 7
            
        if sign == -1 : 
            digits.append("-")
            
        return "".join(reversed(digits))

4. Conclusion