[leetcode]504. Base 7

Given an integer, return its base 7 string rePResentation.

Example 1:

Input: 100Output: "202"
Example 2:
Input: -7Output: "-10"
Note:The input will be in range of [-1e7, 1e7].
Answer:
public String convertToBase7(int num) {       return Long.toString(Long.valueOf(num),7);}