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: Time Limit Exceeded)

#include <stdio.h>
#include <limits.h>
int main(void)
{
    int n;
    scanf("%d",&n);
    long n_max=0,n_min=LONG_MAX;
    long doll[200000]={};
    int i;

    for(i=0;i<n;i++)
    {
        scanf("%d",&doll[i]);
        if(doll[i]>n_max)
        {
            n_max=doll[i];
        }
        if(doll[i]<n_min)
        {
            n_min=doll[i];
        }
    }



    int j;
    long max=LONG_MIN;
    long flag=n_max-n_min;
    int tem=0;

    for(i=0;i<n;i++)
    {
        if(n_max-doll[i]>max)
        {
            for(j=i+1;j<n;j++)
            {
                if(doll[j]-doll[i]>max)
                {
                    max=doll[j]-doll[i];
                    if(flag==max)
                    {
                        tem=1;
                        break;
                    }
                }
            }
        }
        if(tem==1)
        {
            break;
        }
    }
    printf("%d\n",max);

    return 0;
}