| Subtask no. | Testdata Range | Constraints | Score | 
|---|---|---|---|
| 1 | 0~4 | 範例測資 | 0 / 0 | 
| 2 | 5~9 | $N = K$ | 3 / 3 | 
| 3 | 1, 10~14 | $N = K + 1$ | 7 / 7 | 
| 4 | 2, 15~24 | $N = 2K$,且 $a_1, a_2, \ldots, a_K$ 任兩數字皆不相同 | 22 / 22 | 
| 5 | 3, 15~34 | $N = 2K$ | 25 / 25 | 
| 6 | 0~4, 35~44 | $N \leq 2000$ | 12 / 12 | 
| 7 | 0~64 | 無額外限制 | 31 / 31 |