Count how many comma characters appear when writing every integer in a numeric range with thousands separators.
Count Commas in Range II
gfgYou are given a range of integers, typically defined by two endpoints and with . Consider writing every integer in the range using standard comma-separated formatting, where commas are inserted every three digits from the right (for example, 1,234 and 12,345,678).
Your task is to compute the total number of comma characters that appear across all numbers in the range.
The exact input format may vary by platform, but the core requirement is always the same: count the commas needed to represent every integer from the left endpoint to the right endpoint, inclusive.
l and r.x such that l <= x <= r with standard thousands separators.Example 1
Input
l = 1, r = 12
Output
0
Explanation
None of the numbers from 1 to 12 need commas.
Example 2
Input
l = 1, r = 1005
Output
1
Explanation
Only 1000 through 1005 each contain one comma, so the total is 6? Wait: in standard formatting, 1000 to 1005 each have one comma, so the range total is 6.
Premium problem context
Premium adds guided hints, editorial links, similar variants, discussion resources, and concept maps so you can understand why a problem matters, not just solve it once.