Description
You are given an integer n.
Return the total number of commas used when writing all integers from [1, n] (inclusive) in standard number formatting.
In standard formatting:
- A comma is inserted after every three digits from the right.
- Numbers with fewer than 4 digits contain no commas.
Example 1:
Input: n = 1002
Output: 3
Explanation:
The numbers "1,000", "1,001", and "1,002" each contain one comma, giving a total of 3.
Example 2:
Input: n = 998
Output: 0
Explanation:
All numbers from 1 to 998 have fewer than four digits. Therefore, no commas are used.
Constraints:
1 <= n <= 105
Solutions
Seemed like it might include some crazy math tricks, but the restriction of max n = 100_000 is too low.
Language: javascript(2026-09-08 08:13)DONE
CPU Performance100.00%
Memory Performance74.19%
/**
* @param {number} n
* @return {number}
*/
var countCommas = function(n) {
return Math.max(0, n - 999);
};