Problem:
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Maximum Profit

You can obtain profits from foreign exchange margin transactions. For example, if you buy 1000 dollar at a rate of 100 yen per dollar, and sell them at a rate of 108 yen per dollar, you can obtain (108 - 100) × 1000 = 8000 yen.

Write a program which reads values of a currency $R_t$ at a certain time $t$ ($t = 0, 1, 2, ... n-1$), and reports the maximum value of $R_j - R_i$ where $j > i$ .

Input

The first line contains an integer $n$. In the following $n$ lines, $R_t$ ($t = 0, 1, 2, ... n-1$) are given in order.

Output

Print the maximum value in a line.

Constraints

$2 \leq n \leq 200,000$

$1 \leq R_t \leq 10^9$

Sample Input 1

6
5
3
1
3
4
3

Sample Output 1

3

Sample Input 2

3
4
3
2

Sample Output 2

-1

Solution in JAVA (judge verdict: Time Limit Exceeded)

import java.io.*;
 
class Main {
    public static void main(String[] args) {
        BufferedReader kb = new BufferedReader( new InputStreamReader( System.in ) );
        try {
            int n = Integer.parseInt( kb.readLine() );
			
			int[] nums = new int[n];
            int num, maxprofit;
            int i, j;
            
            maxprofit = 1-1000000000;
            for( i=0; i<n; i++ ) {
            	num = Integer.parseInt( kb.readLine() );
            	nums[i] = num;
				for( j=0; j<i; j++ ) {
					maxprofit = Math.max( maxprofit, num-nums[j] );
				}
            }
            
            System.out.println( maxprofit  );
             
            kb.close();
        } catch( IOException e ) {
            System.err.println( e );
        }
    }
}