[Solved] Langford Pairing Contest Problem
![[Solved] Langford Pairing Contest Problem](https://realcoder.techss24.com/wp-content/uploads/2022/06/Solved-Langford-Pairing-Contest-Problem.png "[Solved] Langford Pairing Contest Problem")
Langford Pairing: You are given a positive integer N. Return a list of integers of size 2N containing all the integers from 1 to N (both inclusive) twice arranged according to Langford pairing. If no such pairing exists return -1 is…