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: Wrong Answer)

import java.util.Scanner;

public class Main {
	public static Scanner scan = new Scanner(System.in);
	public static int n;
	public static void main(String args[]){
		run();
	}
	static void run(){
		int n, firstPriceTmp, priceTmp;
		int minPrice, maxPrice;
		int maxBenefit, benefit;
		
		maxBenefit = -(1000000000 - 1);
		minPrice = 200000;
		maxPrice = 2;
		n = scan.nextInt();
		
		firstPriceTmp = scan.nextInt();
		for(int i = 1; i < n; i++){
			priceTmp = scan.nextInt();
			minPrice = Math.min(minPrice, firstPriceTmp);
			firstPriceTmp = priceTmp;
			benefit = priceTmp - minPrice;
			maxBenefit = Math.max(benefit, maxBenefit);
		}
		System.out.println(maxBenefit);
	}
}