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September 8Easy

Count commas in range

  • Math

Problem

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.

Solution

class Solution:
    def countCommas(self, n: int) -> int:
        return max(0, n - 999)