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:]
}