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=;
 const int mod=1e9+;
 int a[N];
 int main()
 {
     std::ios::sync_with_stdio(false);
     int n;
     while(cin>>n){
         for(int i=;i<=n;++i){
             cin>>a[i];
         }
         if(n&){
             cout<<a[n];
             for(int i=n-;i>=;i-=)
                 cout<<" "<<a[i];
             for(int i=;i<=n-;i+=)
                 cout<<" "<<a[i];
             cout<<endl;
         }else{
             cout<<a[n];
             for(int i=n-;i>=;i-=)
                 cout<<" "<<a[i];
             for(int i=;i<=n-;i+=)
                 cout<<" "<<a[i];
             cout<<endl;
         }
     }
     return ;
 }