Person in charge

• cq_irritater

Problem Description

1. In Linux terminal, which command is used to create a new directory:

{{ select(1) }}

• newdir
• mkdir
• create
• mkfold

2. (Multiple Choice) Which of the following connected undirected graphs are not necessarily colorable with at most two colors:

{{ multiselect(2) }}

• Complete ternary tree
• Planar graph
• Edge-biconnected graph
• Eulerian graph

3. Given $n$ pillars, you need to sequentially place rings numbered $1,2,3,\ldots$ following these rules:
   • Each pillar is fixed at the bottom and open at the top for placing rings
   • When placing a ring on top of any pillar, the sum of numbers on any two adjacent rings must be a perfect square Calculate the maximum number of rings that can be placed when there are {{ input(3) }} pillars.