AtCoder Grand Contest 061
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Problem Statement
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There is an array $A_1, \ldots, A_N$, and initially $A_i = i$ for all $i$. Define the following routine $\mathrm{shuffle}(L, R)$:
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- If
$R = L + 1$, swap values of$A_L$and$A_R$and terminate. - Otherwise, run
$\mathrm{shuffle}(L, R - 1)$followed by$\mathrm{shuffle}(L + 1, R)$.
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Suppose we run $\mathrm{shuffle}(1, N)$. Print the value of $A_K$ after the routine finishes.
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For each input file, solve $T$ test cases.
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Constraints
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$1 \leq T \leq 1000$$2 \leq N \leq 10^{18}$$1 \leq K \leq N$
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Input
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The input is given from Standard Input in the following format:
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T
case_1
case_2
\vdots
case_T
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Each case is in the following format:
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N K
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Output
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Print $T$ lines. The $i$-th line should contain the answer for the $i$-th case.
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样例
Input #1
7
2 1
2 2
5 1
5 2
5 3
5 4
5 5
Output #1
2
1
2
4
1
5
3
For $N=2$, we do the following and get $A=(2,1)$.
- Run $\mathrm{shuffle}(1, 2)$, and swap $A_1$ and $A_2$.
For $N=5$, we do the following and get $A=(2,4,1,5,3)$.
- Run $\mathrm{shuffle}(1, 5)$:
- Run $\mathrm{shuffle}(1, 4)$:
- Run $\mathrm{shuffle}(1, 3)$:
- $\vdots$
- Run $\mathrm{shuffle}(2, 4)$:
- $\vdots$
- Run $\mathrm{shuffle}(2, 5)$:
- Run $\mathrm{shuffle}(2, 4)$:
- $\vdots$
- Run $\mathrm{shuffle}(3, 5)$:
- $\vdots$
题目信息
题面与样例版权归 AtCoder 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。