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Limite de temps : 2 s Limite de mémoire : 1024 MB Points totaux : 100 Hackable ✓

#18584. MEXMEX

Statistiques

$\textrm{MEX}$ 是一個尋找集合中未包含的最小非負整數的函數。例如,$\textrm{MEX}(\{0,1,3,4\})=2$ 且 $\textrm{MEX}(\{1,2,4\})=0$。

ibasic 對於一個長度為 $N$ 且由非負整數組成的數列 $A$,定義了 $\textrm{MEXMEX}$ 函數如下: $$\textrm{MEXMEX}(A)=\textrm{MEX}(\{\textrm{MEX}(\{A_l,A_{l+1},\dots,A_r\})\mid 1\le l\le r\le N\})$$

也就是說,$\textrm{MEXMEX}(A)$ 是先計算數列 $A$ 的所有連續子序列中,每個子序列所構成集合的 $\textrm{MEX}$ 值,再對這些值所組成的集合取 $\textrm{MEX}$。

請幫 ibasic 找出一個長度為 $N$ 的數列 $A$,使得 $\textrm{MEXMEX}(A)=K$。

第一行包含兩個整數 $N$ 和 $K$,以空白分隔。$(1\le N\le 2\times 10^5;$ $0\le K\le N+1)$

第一行輸出滿足條件的數列 $A_1, A_2, \dots, A_N$,以空白分隔。$(0\le A_i\le 2^{31}-1)$

若不存在滿足條件的數列,則輸出 -1。若存在多種可能的數列,輸出其中任意一個即可。

範例

輸入格式 1

6 7

輸出格式 1

0 1 2 3 4 5

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