Problem:
MathJax.Hub.Config({ tex2jax: { inlineMath: [["$","$"], ["\\(","\\)"]], processEscapes: true }});

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: Accepted)

import java.sql.Array;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
public class Main{
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		int len = scanner.nextInt();
		List<Integer> nums = new ArrayList<Integer>() ;
		for (int i = 0; i < len; i++) {
			nums.add(scanner.nextInt());
		}
		
		int min = nums.get(0);
		int profit = -1000000000;
		for (int i = 1; i < len; i++) {
			if (profit<(nums.get(i)-min)) {
				profit = nums.get(i)-min;
			}
			if (nums.get(i)<min) {
				min = nums.get(i);
			}
		}
		
		System.out.println(profit);
	}

}