Base 7

Given an integer, return its base 7 string representation.

Example 1:

Input: 100
Output: "202"

Example 2:

Input: -7
Output: "-10"

Note: The input will be in range of [-1e7, 1e7].

public class Solution {
    public String convertToBase7(int num) {
        if (num == 0) return "0";
        
        StringBuffer result = new StringBuffer();
        Boolean isNegative = false;
        if (num < 0) {
            isNegative = true;
            num = -num;
        }
        
        while (num != 0) {
            int insertMe = num % 7;
            result.insert(0, Integer.toString(insertMe));
            num /= 7;
        }
        if (isNegative) result.insert(0, "-");
        return result.toString();
    }
}

public class Solution {
    public String convertToBase7(int num) {
        if (num == 0) return "0";
        
        Boolean isNegative = num < 0;
        num = Math.abs(num);
        
        String result = "";
        while (num != 0) {
            result = Integer.toString(num % 7) + result;
            num /= 7;
        }
        return isNegative ? "-" + result : result;
    }
}