MathDB
Lamps to be turned on in at most $k$ moves

Source: Macedonian TST 2022, P1

May 21, 2022
combinatoricsTST

Problem Statement

Let nn be a fixed positive integer. There are n1n \geq 1 lamps in a row, some of them are on and some are off. In a single move, we choose a positive integer ii (1in1 \leq i \leq n) and switch the state of the first ii lamps from the left. Determine the smallest number kk with the property that we can make all of the lamps be switched on using at most kk moves, no matter what the initial configuration was.
Proposed by Viktor Simjanoski and Nikola Velov