Problem: 2062C - Cirno and Operations
Language: java

Solution 1 (runtime: 140 ms):
import java.io.*;
import java.util.*;

public class Main {

    public static void main(String[] args) throws IOException {
        InputReader scan = new InputReader(System.in);
        PrintWriter pw = new PrintWriter(System.out);

        int t = scan.nextInt();
        while (t --> 0) {
            int n = scan.nextInt();
            long[] a = new long[n];
            for (int i = 0; i < n; i++) {
                a[i] = scan.nextLong();
            }

            long maxSum = 0;
            for (int i = 0; i < n; i++) {
                maxSum += a[i];
            }

            for (int i = 0; i < n-1; i++) {
                long sum = 0;
                for (int j = 0; j < n-i-1; j++) {
                    a[j] = a[j+1] - a[j];
                    sum += a[j];
                }
                maxSum = Math.max(maxSum, Math.abs(sum));
            }

            pw.println(maxSum);
        }

        pw.close();
    }
    static class InputReader {

        private final InputStream stream;
        private final byte[] buf = new byte[8192];
        private int curChar, snumChars;
        private SpaceCharFilter filter;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        public int snext() {
            if (snumChars == -1)
                throw new InputMismatchException();
            if (curChar >= snumChars) {
                curChar = 0;
                try {
                    snumChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (snumChars <= 0)
                    return -1;
            }
            return buf[curChar++];
        }

        public int nextInt() {
            int c = snext();
            while (isSpaceChar(c))
                c = snext();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = snext();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = snext();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public long nextLong() {
            int c = snext();
            while (isSpaceChar(c))
                c = snext();
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = snext();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = snext();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public int[] nextIntArray(int n) {
            int a[] = new int[n];
            for (int i = 0; i < n; i++)
                a[i] = nextInt();
            return a;
        }

        public String readString() {
            int c = snext();
            while (isSpaceChar(c))
                c = snext();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = snext();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            if (filter != null)
                return filter.isSpaceChar(c);
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);
        }
    }
}


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);
    }





}