Given an integer n, add a dot (".") as the thousands separator and return it in string format.
Example 1:
Input: n = 987
Output: "987"
Example 2:
Input: n = 1234
Output: "1.234"
Example 3:
Input: n = 123456789
Output: "123.456.789"
Example 4:
Input: n = 0
Output: "0"
Constraints:
0 <= n < 2^31
Solution:
class Solution {
public String thousandSeparator(int n) {
if (n == 0) return "0";
StringBuilder sb = new StringBuilder();
int i = 0;
while (n > 0) {
if (i > 0 && i % 3 == 0) {
sb.append(".");
}
int val = n % 10;
sb.append(val + "");
n = n / 10;
i ++;
}
return sb.reverse().toString();
}
}