Antitours in Mahishmati
Source: India TST 2023 Day 1 P1
July 9, 2023
combinatoricsgraph theory
Problem Statement
In the fictional country of Mahishmati, there are cities, including a capital city. Some pairs of cities are connected by two-way flights. Given a city , an ordered list of cities is called an antitour from if[*] every city (including ) appears in the list exactly once, and
[*] for each , it is impossible to go from to by a sequence of exactly (not necessarily distinct) flights.Baahubali notices that there is an antitour from for any city . Further, he can take a sequence of flights, starting from the capital and passing through each city exactly once. Find the least possible total number of antitours from the capital city.Proposed by Sutanay Bhattacharya