Official algorithmic problem description and constraints.
You're given two positive integers L and R Let N=R−L+1. Consider the array A=[L,L+1,L+2,…,R] of length N that contains every integer from L to R exactly once, in order. Find any array B of length N such that: Every integer from L to R appears exactly once in B; and For each , gcd gcd(A i ,B i )=1. If no such B exists, print − 1 −1 instead.
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