Case #1: Possible
3
1 2 5
Case #2: Impossible
Case #3: Possible
2
5
Case #4: Possible
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Case #5: Possible
8 3
1 5
Case #6: Impossible