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 C (judge verdict: Accepted)

#include<stdio.h>

int main(){


int n;
scanf("%d",&n);
long long arr[200000] = {0};
scanf("%lli %lli",&arr[0],&arr[1]);
long long min = arr[0];
long long dif = arr[1] - arr[0];
long long max = dif;
for(int i=2;i<n;i++){
	scanf("%lli",&arr[i]);
}
for(int i=1;i<n;i++){

	if(min>arr[i-1])
	min = arr[i-1];

	dif = arr[i] - min;
	if(dif>max)
	max = dif;
}
printf("%lli\n",max);






	return 0;
}