题解 | #操作序列#

使用deque前后交替插入

根据n的奇偶判断正向输出还是逆向输出

#include <iostream>
#include <algorithm>
#include <deque>
#include <vector>
#include <string>
#include <iterator>
using namespace std;

int main(void)
{
    int n;
    cin >> n;
    vector<int> seq(n);
    for( int i = 0; i < n; ++i ){
        cin >> seq[i];
    }
    
    deque<int> b;
    for( int i = 0; i < n; ++i ){
        if( i % 2 ){
            b.push_back(seq[i]);
        } else {
            b.push_front(seq[i]);
        }
    }
    
    if( n % 2 ){
        copy(b.cbegin(), b.cend(), ostream_iterator<int>(cout, " "));
    } else {
        copy(b.crbegin(), b.crend(), ostream_iterator<int>(cout, " "));
    }
}