504. Base 7

Description

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].

Solution

/**
 * @param {number} num
 * @return {string}
 */
var convertToBase7 = function(num) {
    "use strict";
    if (num === 0) {
        return "0";
    }
    let negFlag = false;
    if (num < 0) {
        num = -num;
        negFlag = true;
    }
    let result = "";
    while (num) {
        result += (num % 7);
        num = Math.floor(num / 7);
    }
    result = result.split("").reverse().join("");
    return negFlag ? "-" + result : result;
};