(Leetcode)504. Base 7

Given an integer, return its base 7 string representation.

Example 1:
Input: 100
Output: "202"
Example 2:
Input: -7
Output: "-10"

Solution:

public class Solution {    public String convertToBase7(int num) {        StringBuilder sb = new StringBuilder();        boolean flag = true;    // 标记num 符号        if (num == 0){            return "0";        }        if(num < 0) {            flag = false;        }        while (num != 0) {            sb.append(Math.abs(num) % 7);            num = num / 7;        }        if (!flag) {            return "-" + sb.reverse().toString();        }        return sb.reverse().toString();    }}