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)

//
// Created by syakushimo nekomo on 2018/02/28.
//
#include <stdio.h>
int main(void) {
    int n=0;
    scanf("%d",&n);
    int max;
    int min;
    int difference;
    int tmp;
    scanf("%d",&tmp);
    scanf("%d",&min);
    difference=min-tmp;
    max=min;
    if(tmp<min)
    {
        min=tmp;
    }
    for(int i=2;i<n;i++)
    {
        //最大値が更新される度に最小値と比較する
        scanf("%d",&tmp);
        if(tmp>=max){
            max = tmp;
            if(max-min>difference)
            {
                difference = max - min;
            }
        }else if(tmp<=min)
        {
            min=tmp;
            //それ以前の最高値は無意味なのでminに合わせる
            max=min;
        }
    }
    printf("%d\n",difference);
}