MathDB
increase a number by 1 and decrease another number by 1.

Source: Moldova TST 2011, day 2, problem 4

March 8, 2011
combinatorics unsolvedcombinatorics

Problem Statement

Initially, on the blackboard are written all natural numbers from 11 to 2020. A move consists of selecting 22 numbers a<ba<b written on the blackboard such that their difference is at least 22, erasing these numbers and writting a+1a+1 and bāˆ’1b-1 instead. What is the maximum numbers of moves one can perform?
Back to ProblemsView on AoPS