PROBLEM LINK:
Practice
Contest: Division 1
Contest: Division 2
Contest: Division 3
Contest: Division 4
Author: raysh07
Tester: tabr
Editorialist: iceknight1093
DIFFICULTY:
TBD
PREREQUISITES:
None
PROBLEM:
A TV has X channels, of which the even-numbered ones stopped working.
How many channels are still working?
EXPLANATION:
The working channels are 1, 3, 5, \ldots — all the odd numbers upto X.
Since X is small, it is possible to count all such odd numbers by writing a loop.
Alternately, it can be seen that:
- If X is even, exactly half the channels will remain. So, the answer is \frac{X}{2}.
- If X is odd, a bit more than half the channels will remain: \frac{X+1}{2}.
TIME COMPLEXITY:
\mathcal{O}(1) per testcase.
CODE:
Editorialist's code (Python)
x = int(input())
if x%2 == 0: print(x//2)
else: print(x//2 + 1)