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 n,i,j,minv,maxv;
    scanf("%d",&n);
    int R[n];
    for(i = 0;i < n;i++)
    {
        scanf("%d",&R[i]);
    }
    maxv = R[1] - R[0];
    minv = R[0];
    for(j = 1;j < n;j++)
    {
        if(maxv < R[j] - minv)
        {
            maxv = R[j] - minv;
        }
        if(minv > R[j])
        {
            minv = R[j];
        }
    }
    printf("%d\n",maxv);
    return 0;
}