Mad scientist writes numbers
Source: India EGMO 2021 TST P1
November 18, 2021
discrete systeminvariant
Problem Statement
Mad scientist Kyouma writes positive integers on a board. Each second, he chooses two numbers written on the board with , and writes the number on the board. After some time, he sends the list of all the numbers on the board to Christina. She notices that all the numbers from 1 to 1000 are present on the list. Aid Christina in finding the minimum possible value of N.