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.util.Scanner;
public class Main{
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);		int n = scan.nextInt();
		long[] data = new long[n];
		long max = 0;
		for(int i = 0 ; i < n ; i++){
			data[i]=scan.nextLong();
		}
		//long min = Long.MAX_VALUE;
		max=data[1]-data[0];
		for(int i = 0 ; i < n ; i ++){
			/*if (data[i]>max) {
                continue;
            }*/
			for(int j = n-1 ; j > i ; j --){
				if(max<(data[j]-data[i])){
					max= data[j]-data[i];
				}
				//System.out.println(data[i]-data[j]);
			}
		}
		System.out.println(max);
	}
}