| Subtask no. | Testdata Range | Constraints | Score | 
|---|---|---|---|
| 1 | 0~1 | 範例測資 | 0 / 0 | 
| 2 | 2~21 | $1 \leq N, M, A, B \leq 3 \times 10^ 4, 1 \leq K \leq 2 \times 10^ {18}$ | 30 / 30 | 
| 3 | 0, 2~72 | $1 \leq N, M, A, B \leq 10^ 9, 1 \leq K \leq 2 \times 10^ {18}$ | 30 / 30 | 
| 4 | 0~99 | 無額外限制 | 40 / 40 |