牛客网 2018校招真题 网易 操作序列

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Description

牛客网 2018校招真题 操作序列

Solving Ideas

规律题，对于长度为n的序列a

• 如果 n 为偶数，则结果为
  a[n-1], a[n-3], a[n-5], ...,a[3], a[1], a[0], a[2], a[4], ..., a[n - 2]
• 如果 n 为奇数，则结果为
  a[n-1], a[n-3], a[n-5], ..., a[2], a[0], a[1], a[3], a[5], ..., a[n - 2]

Time complexity : O(n)
Space complexity : O(n)

Solution

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 * @author wylu
 */
public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(br.readLine());
        String[] strs = br.readLine().split(" ");

        StringBuilder sb = new StringBuilder();
        int i;
        for (i = n - 1; i >= 0; i -= 2) sb.append(strs[i]).append(" ");
        for (i = (n % 2 == 0) ? 0 : 1; i < n - 2; i += 2) sb.append(strs[i]).append(" ");
        sb.append(strs[i]);
        System.out.println(sb);
    }
}