README.md

1556. Thousand Separator

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

Solutions (Rust)

1. Solution

impl Solution {
    pub fn thousand_separator(n: i32) -> String {
        let s = n.to_string();
        let v = s.split("").filter(|&c| c != "").collect::<Vec<_>>();
        let v = v.rchunks(3).rev().map(|c| c.concat()).collect::<Vec<_>>();

        v.join(".")
    }
}