A14063. Favorite Sequence
编程题
普及/提高-
知识点
题目描述
Polycarp has a favorite sequence $a[1 \dots n]$ consisting of $n$ integers. He wrote it out on the whiteboard as follows:
- he wrote the number $a_1$ to the left side (at the beginning of the whiteboard);
- he wrote the number $a_2$ to the right side (at the end of the whiteboard);
- then as far to the left as possible (but to the right from $a_1$ ), he wrote the number $a_3$ ;
- then as far to the right as possible (but to the left from $a_2$ ), he wrote the number $a_4$ ;
- Polycarp continued to act as well, until he wrote out the entire sequence on the whiteboard.
The beginning of the result looks like this (of course, if $n \ge 4$ ).For example, if $n=7$ and $a=[3, 1, 4, 1, 5, 9, 2]$ , then Polycarp will write a sequence on the whiteboard $[3, 4, 5, 2, 9, 1, 1]$ .
You saw the sequence written on the whiteboard and now you want to restore Polycarp's favorite sequence.
- he wrote the number $a_1$ to the left side (at the beginning of the whiteboard);
- he wrote the number $a_2$ to the right side (at the end of the whiteboard);
- then as far to the left as possible (but to the right from $a_1$ ), he wrote the number $a_3$ ;
- then as far to the right as possible (but to the left from $a_2$ ), he wrote the number $a_4$ ;
- Polycarp continued to act as well, until he wrote out the entire sequence on the whiteboard.
The beginning of the result looks like this (of course, if $n \ge 4$ ).For example, if $n=7$ and $a=[3, 1, 4, 1, 5, 9, 2]$ , then Polycarp will write a sequence on the whiteboard $[3, 4, 5, 2, 9, 1, 1]$ .
You saw the sequence written on the whiteboard and now you want to restore Polycarp's favorite sequence.
输入格式
The first line contains a single positive integer $t$ ( $1 \le t \le 300$ ) — the number of test cases in the test. Then $t$ test cases follow.
The first line of each test case contains an integer $n$ ( $1 \le n \le 300$ ) — the length of the sequence written on the whiteboard.
The next line contains $n$ integers $b_1, b_2,\ldots, b_n$ ( $1 \le b_i \le 10^9$ ) — the sequence written on the whiteboard.
The first line of each test case contains an integer $n$ ( $1 \le n \le 300$ ) — the length of the sequence written on the whiteboard.
The next line contains $n$ integers $b_1, b_2,\ldots, b_n$ ( $1 \le b_i \le 10^9$ ) — the sequence written on the whiteboard.
输出格式
Output $t$ answers to the test cases. Each answer — is a sequence $a$ that Polycarp wrote out on the whiteboard.
输入输出样例
输入 #1
6 7 3 4 5 2 9 1 1 4 9 2 7 1 11 8 4 3 1 2 7 8 7 9 4 2 1 42 2 11 7 8 1 1 1 1 1 1 1 1
输出 #1
3 1 4 1 5 9 2 9 1 2 7 8 2 4 4 3 9 1 7 2 8 7 42 11 7 1 1 1 1 1 1 1 1
说明/提示
In the first test case, the sequence $a$ matches the sequence from the statement. The whiteboard states after each step look like this:
$[3] \Rightarrow [3, 1] \Rightarrow [3, 4, 1] \Rightarrow [3, 4, 1, 1] \Rightarrow [3, 4, 5, 1, 1] \Rightarrow [3, 4, 5, 9, 1, 1] \Rightarrow [3, 4, 5, 2, 9, 1, 1]$ .
$[3] \Rightarrow [3, 1] \Rightarrow [3, 4, 1] \Rightarrow [3, 4, 1, 1] \Rightarrow [3, 4, 5, 1, 1] \Rightarrow [3, 4, 5, 9, 1, 1] \Rightarrow [3, 4, 5, 2, 9, 1, 1]$ .