PROBLEM LINK:
Practice
Contest: Division 1
Contest: Division 2
Contest: Division 3
Contest: Division 4
Author: iceknight1093
Tester: raysh07
Editorialist: iceknight1093
DIFFICULTY:
Cakewalk
PREREQUISITES:
None
PROBLEM:
Chef cleans on days 10, 20, 30, \ldots, i.e. all multiples of 10.
Today is day number N. How many days is it till the next cleaning day?
EXPLANATION:
Let r denote the last digit of N. Equivalently, this is the remainder when N is divided by 10.
Then, 10-r days are needed to get to the next multiple of 10, and so this is the answer.
r can be obtained via the expression n % 10 in most programming languages.
TIME COMPLEXITY:
\mathcal{O}(1) per testcase.
CODE:
Editorialist's code (PyPy3)
n = int(input())
print(10 - n%10)