1556. Thousand Separator

Easy
​
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"
Constraints:
  • 0 <= n <= 231 - 1
​

解題

func thousandSeparator(n int) string {
if n < 1000 { return strconv.Itoa(n) }
ans := ""
for n>0 {
s := strconv.Itoa(n % 1000)
if n >= 1000 {
if len(s)==1 {
s = "00"+s
} else if len(s)==2 {
s = "0"+ s
}
}
ans = "." + s + ans
n = n/1000
}
return ans[1:]
}
​