Code RoomSum of digits to n
MediumPrep Room Coding #1467

Sum of digits to n

CodingAlgorithms & data structuresMid–Senior~25 min

Compute the sum of the decimal digits of every integer from 1 to n inclusive. For example for n = 12 the total is (1)+(2)+...+(9)+(1+0)+(1+1)+(1+2) = 51. Return the total. 1 <= n <= 10^12.

Implement
total_digit_sum(n: int) → int
Examples
in[12]out51
What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

0:00 of about 25 min
InputExpectedGot
[12]51not run yetsample