Problem: 2062C - Cirno and Operations
Language: java

Solution 1 (runtime: 311 ms):

import java.util.Scanner;

public class Sol {
    static Scanner rd = new Scanner(System.in);
    public static void main(String[] args) {
        int tt = rd.nextInt();
        while (tt-- > 0) {
            new Solution().solve();
        }
    }

    static class Solution {
        void solve() {
            int n = rd.nextInt();
            long[] a = new long[n];

            for (int i = 0; i < n; i++) {
                a[i] = rd.nextInt();
            }
            int len = n;
            if (len == 1) {
                System.out.println(a[0]);
                return;
            }
            long max = getSum(a, n, false);
            while (len > 1) {
                for (int i = 0; i < len - 1; i++) {
                    a[i] = a[i + 1] - a[i];
                }
                len--;
                max = Math.max(Math.max(getSum(a, len, true), getSum(a, len, false)), max);
            }
            System.out.println(max);
        }

        long getSum(long[] a, int len, boolean neg) {
            long sum = 0;
            for (int i = 0; i < len; i++) {
                if (neg) {
                    sum += (-1) * a[i];
                } else {
                    sum += a[i];
                }
            }
            return sum;
        }
    }
}


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);
    }





}