ACM14KG2 - Editorial

PROBLEM LINK:

Practice
Contest

Author: Anudeep Nekkanti
Tester: Mahbubul Hasan
Editorialist: Jingbo Shang

DIFFICULTY:

Cakewalk

PREREQUISITES:

Basic Programming

PROBLEM:

There are N people in a circle. And a ball is passing clockwise starting from the a-th person (index is 1-based). Asking for the index of the person with the ball after M passes.

EXPLANATION:

If the index is 0-based, the answer could be easily get using the mod operations. Therefore, we first transform the number to 0-based, i.e. a-th person is (a-1) in 0-based.

Then, the answer in 0-based should be (a-1+M)%N.

Finally, the answer in 1-based is (a-1+M)%N+1.

AUTHOR’S AND TESTER’S SOLUTIONS:

Solutions will be available soon.

Author’s solution can be found here.
Tester’s solution can be found here.