• + 12 comments

    Simple solution in Python 3:

    def minimum_distance(n, A):
        for d in range(1, n):
            for i in range(n - d):
                if A[i] == A[i+d]:
                    return d
        return -1
    
    print(minimum_distance(int(input()), [int(x) for x in input().split()]))