A. Favorite Sequence

https://codeforces.ml/contest/1462/problem/A

题意：有个数组A{1,2,3,4,5…n},现在按左一个右一个的方式赋给数组B，B数组就会变成{1,3,5…n-2,n,n-1,…6,4,2}。现在告诉你了数组B，让你求出数组A。

创建两个指针l跟r，分别从头跟尾向中间扫就行，注意边界条件是l<=r(在n为奇数的情况下最终l=r)

#include <iostream>
using namespace std;

int main() {
	int t;
	cin >> t;
	while (t--) {
		int a[301];
		int b[301];
		int n;
		cin >> n;
		for (int i = 0; i < n; i++) {
			cin >> a[i];
		}
		int l = 0;
		S
		int r = n - 1;
		int k = 0;
		while (l <= r) {
			b[k] = a[l];
			k++;
			b[k] = a[r];
			k++;
			l++, r--;
		}
		for (int i = 0; i < n; i++) {
			cout << b[i] << " ";
		}
		cout << endl;
	}
	return 0;
}