Problem: 2062C - Cirno and Operations
Language: java

Solution 1 (runtime: 343 ms):
import java.util.*;
public class CF_1001_3 {
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        int t=sc.nextInt();
        while(t-->0){
            int n=sc.nextInt();
            ArrayList<Long> list=new ArrayList<>();
            long sum=0;
            long max=Long.MIN_VALUE;
            for(int i=0;i<n;i++){
                list.add((long) sc.nextInt());
                sum+=list.get(i);
            }
            max=Math.max(max,sum);
            for(int i=0;i<n-1;i++){
                long sum1=0;
                ArrayList<Long> temp1=new ArrayList<>();
                for(int j=1;j<list.size();j++){
                    temp1.add(list.get(j)-list.get(j-1));
                    sum1+=list.get(j)-list.get(j-1);
                }
                long sum2=0;
                Collections.reverse(list);
                ArrayList<Long> temp2=new ArrayList<>();
                for(int j=1;j<list.size();j++){
                    temp2.add(list.get(j)-list.get(j-1));
                    sum2+=list.get(j)-list.get(j-1);
                }
                list.clear();
                if(sum1>sum2){
                    max=Math.max(max,sum1);
                    for(int j=0;j<temp1.size();j++){
                        list.add(temp1.get(j));
                    }
                }else{
                    max=Math.max(max,sum2);
                    for(int j=0;j<temp2.size();j++){
                        list.add(temp2.get(j));
                    }
                }
            }
            System.out.println(max);

        }
    }
}


Solution 2 (runtime: 140 ms):
import java.io.*;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;
import java.util.stream.Collectors;



public class Main {
    static int MOD = (int) (1e9+7);
    static InputReader in = new InputReader(System.in);
    static PrintWriter out = new PrintWriter(System.out, false);
    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;
        public int nextInt() {
            return Integer.parseInt(next());
        }
        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }
        public long nextLong() {
            return Long.parseLong(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }
    }
    static List<Long> list = new ArrayList<>();
    public static void main(String[] args) throws Exception {

        Main main = new Main();
        int T = in.nextInt();
        while (T-- > 0){
            main.solve();
        }
        out.flush();
    }

    void solve() {
        int n = in.nextInt();
        List<Long> list = new ArrayList<>();
        long sum = 0;
        for (int i = 0; i < n; i++) {
            long t = in.nextInt();
            list.add(t);
            sum += t;
        }
        long max = sum;
        while (list.size() > 1){
            List<Long> list0 = new ArrayList<>();
            sum = 0;
            for (int i = 1; i < list.size(); i++) {
                long t = list.get(i) - list.get(i - 1);
                list0.add(t);
                sum += t;
            }
            if(sum < 0) sum *= -1;
            max = Math.max(max, sum);
            list = list0;

        }
        out.println(max);
    }





}