UVA Problem ID 11078 (Open Credit System)

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


public class Main {
	public static void main (String args[]) throws IOException
	{
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb=new StringBuilder(1000);
		int testcases=Integer.parseInt(br.readLine());
		for (int t = 0; t < testcases;t++) {
			int n=Integer.parseInt(br.readLine());
			int score[]=new int[n];
			int maxdiff=-99999999,max=-99999999;
			for (int i = 0; i < n; i++) {
				score[i]=Integer.parseInt(br.readLine().trim());
			}
			for (int j =0; j max)
					max=score[j];
				if(max-score[j+1]>maxdiff)
					maxdiff=max-score[j+1];
			}
			sb.append(maxdiff+"\n");
		}
		System.out.print(sb);
	}
}