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(void){
    int n,t,j;
    int r[200000];
    int x;
    int max = 1-1000000000;
    int min ;
    scanf("%d\n",&n);
    for(t=0;t<=n;t++){
        scanf("%d",&r[t]);
        }
    min = r[0];
    for(t=1;t<=n-1;t++){
        x = r[t]-min;
        if(x>max){
            max=x;
        }
        if(r[t]<min){
            min=r[t];
        }
    }
printf("%d\n",max);
return 0;
}