AtCoder Regular Contest 077 C - pushpush

题目链接：http://arc077.contest.atcoder.jp/tasks/arc077_a

Time limit : 2sec / Memory limit : 256MB

Score : 300 points

Problem Statement

You are given an integer sequence of length n, a1,…,an. Let us consider performing the following n operations on an empty sequence b.

The i-th operation is as follows:

1. Append ai to the end of b.
2. Reverse the order of the elements in b.

Find the sequence b obtained after these n operations.

Constraints

• 1≤n≤2×105
• 0≤ai≤109
• n and ai are integers.

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Input

Input is given from Standard Input in the following format:

n
a1 a2 … an

Output

Print n integers in a line with spaces in between. The i-th integer should be bi.

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Sample Input 1

Copy

4
1 2 3 4

Sample Output 1

Copy

4 2 1 3

• After step 1 of the first operation, b becomes: 1.
• After step 2 of the first operation, b becomes: 1.
• After step 1 of the second operation, b becomes: 1,2.
• After step 2 of the second operation, b becomes: 2,1.
• After step 1 of the third operation, b becomes: 2,1,3.
• After step 2 of the third operation, b becomes: 3,1,2.
• After step 1 of the fourth operation, b becomes: 3,1,2,4.
• After step 2 of the fourth operation, b becomes: 4,2,1,3.

Thus, the answer is 4 2 1 3.

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Sample Input 2

Copy

3
1 2 3

Sample Output 2

Copy

3 1 2

As shown above in Sample Output 1, b becomes 3,1,2 after step 2 of the third operation. Thus, the answer is 3 1 2.

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Sample Input 3

Copy

1
1000000000

Sample Output 3

Copy

1000000000

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Sample Input 4

Copy

6
0 6 7 6 7 0

Sample Output 4

Copy

0 6 6 0 7 7

 题解：找规律

#include <iostream>
#include <algorithm>
#include <cstring>
#include <cstdio>
#include <vector>
#include <cstdlib>
#include <iomanip>
#include <cmath>
#include <ctime>
#include <map>
#include <set>
#include <queue>
#include <stack>
using namespace std;
#define lowbit(x) (x&(-x))
#define max(x,y) (x>y?x:y)
#define min(x,y) (x<y?x:y)
#define MAX 100000000000000000
#define MOD 1000000007
#define pi acos(-1.0)
#define ei exp(1)
#define PI 3.141592653589793238462
#define INF 0x3f3f3f3f3f
#define mem(a) (memset(a,0,sizeof(a)))
typedef long long ll;
ll gcd(ll a,ll b){
    return b?gcd(b,a%b):a;
}
const int N=200005;
const int mod=1e9+7;
int a[N];
int main()
{
    std::ios::sync_with_stdio(false);
    int n;
    while(cin>>n){
        for(int i=1;i<=n;++i){
            cin>>a[i];
        }
        if(n&1){
            cout<<a[n];
            for(int i=n-2;i>=1;i-=2)
                cout<<" "<<a[i];
            for(int i=2;i<=n-1;i+=2)
                cout<<" "<<a[i];
            cout<<endl;
        }else{
            cout<<a[n];
            for(int i=n-2;i>=2;i-=2)
                cout<<" "<<a[i];
            for(int i=1;i<=n-1;i+=2)
                cout<<" "<<a[i];
            cout<<endl;
        }
    }
    return 0;
}