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: Accepted)

import java.util.Scanner;

public class Main {
	public static int algoOne(int[] nums) {
		int maxProfit = Integer.MIN_VALUE;
		for (int i = 0; i < nums.length; i++) {
			for (int j = i+1; j < nums.length; j++) {
				if (nums[j] - nums[i] > maxProfit) {
					maxProfit = nums[j] - nums[i];
				}
			}
		}
		return maxProfit;
	}
	
	public static int algoTwo(int[] nums) {
		int maxProfit = Integer.MIN_VALUE;
		int minValue = Integer.MAX_VALUE;
		
		for (int i = 0; i < nums.length; i++) {
			if (nums[i] - minValue > maxProfit) maxProfit = nums[i] - minValue;
			
			if (nums[i] < minValue) minValue = nums[i];
		}
		
		return maxProfit;
	}
	
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		int numNums = scanner.nextInt();
		int[] nums = new int[numNums];
		
		//read numbers
		for (int i = 0; i < numNums; i++) {
			nums[i] = scanner.nextInt();
		}
		
		//run algorithm here
		System.out.println(algoTwo(nums));
		
		scanner.close();
	}
}