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)

#include<stdio.h>
#define N 200000 

int main(void){
int Rt[N], RMAX = 0, RANS = 0, R;
int n, s;
int i, j, k = -1;

scanf("%d",&n);
for(i = 0; i < n; i++){
scanf("%d", &s);
Rt[i] = s;
}	
	RANS = Rt[1] - Rt[0];
for( i = 0; i < n-1; i++){
	RMAX = Rt[i + 1];
		if (k < i){
for( j = i + 1; j < n; j++){
	if( Rt[j] > RMAX) {
		RMAX = Rt[j];
		k = j;
}
		}
		}
			else RMAX = Rt[k];
	R = RMAX - Rt[i] ;
	if(RANS < R)RANS = R;
}
printf("%d\n", RANS);



return 0;
}