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 C (judge verdict: Accepted)

/*ALDS1_1D: Maximum Profit*/

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>

#define N 200000

int main(void){
	int R[N] = {0}, i = 0, n, minv, maxv;

	scanf("%d", &n);

	while(i < n){
		scanf("%d", &R[i++]);
	}

	minv = R[0];
	maxv = R[1] - R[0];
	for(i = 1; i < n - 1; i++){
		if(R[i] < minv){
			minv = R[i];
		}
		if(maxv < R[i+1] - minv) {
			maxv = R[i+1] - minv;
		}
	}

	printf("%d\n", maxv);

	return 0;
}