MathDB
2016 CNMO Grade 10/11 P4

Source: 2016 China Northern MO Grade 10, Problem 4; 2016 China Northern MO Grade 11, Problem 4

February 24, 2020
combinatorics

Problem Statement

Can we put intengers 1,2,,121,2,\cdots,12 on a circle, number them a1,a2,,a12a_1,a_2,\cdots,a_{12} in order. For any 1i<j121\leq i<j\leq12, aiajij|a_i-a_j|\neq|i-j|?