Thousand separator

String

53.6% acceptance

Feb 25, 2026

519

Given an integer n, add a dot (".") as the thousands separator and return it in string format.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn thousand_separator(n: i32) -> String {
    let s = n.to_string();
    let digits: Vec<char> = s.chars().collect();
    let len = digits.len();
    let mut result = String::new();
    for (i, c) in digits.iter().enumerate() {
      if i > 0 && (len - i) % 3 == 0 {
        result.push('.');
      }
      result.push(*c);
    }
    result
  }
}