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: 312 ms):
import java.util.*;
public class cirnoop2
{
   public static void main(String args[])
   {
       Scanner in = new Scanner(System.in);
       int t=in.nextInt();
       while(t!=0)
       {
           t--;
           int n=in.nextInt();
           long arr[]=new long[n];
           int i,j;
           long s=0,max=0;
           
           for(i=0;i<n;i++)
           {
               arr[i]=in.nextInt();
               s=s+arr[i];
           }
           if(n==1)
           {
               System.out.println(arr[0]);
           }          
           else
           {
           
           max=Math.max(s,-(long)Math.pow(10,18));
           while(n>=1)
           {
               
               
               --n;
               
               s=0;
               
               for(i=0;i<n;i++)
               {
                   arr[i]=arr[i+1]-arr[i];
                   s=s+arr[i];
               }
               arr[n]=0;
               
              
               s=Math.abs(s);
               max=Math.max(s,max);
           }
           System.out.println(max);
           }
           
   }
}
}