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>

int main()
{
 int i,j,n,max,min;

 /*整数ｎを入力*/
 scanf("%d",&n);
 int R[n];

 /*R(t)を入力*/
for(i=0;i<n;i++)
    {
     scanf("%d",&R[i]);
    }   

 /*最大値最小値の初期値入力*/
 min=R[0];
 max=R[1]-min;

for(i=2;i<n;i++){
     /*最大値最小値の更新*/
    if(R[i-1]<min){
        min=R[i-1];
    }
    if(R[i]-min>max){
        max = R[i]-min;
    }
    
}
 /*最大値の表示*/
printf("%d\n",max);
    
    return 0;
}