【Aizu ALDS1_1_D --- Maximum Profit】

Description

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 Rt at a certain time t (t=0,1,2,…n−1), and reports the maximum value of Rj−Ri where j>i .

Input

The first line contains an integer n. In the following n lines, Rt (t=0,1,2,…n−1) are given in order.

2≤n≤200,000
1≤Rt≤10⁹

Output

Print the maximum value in a line.

Sample Input

6
5
3
1
3
4
3

Sample Output

3

AC代码：

#include <iostream>
#include <algorithm>
using namespace std;
#define MAXN 200010
int arr[MAXN];

int main()
{
    std::ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n;
    cin >> n;
    for(int i=0;i<n;i++)
        cin >> arr[i];
    
    int minn = arr[0];
    int maxx = -0x3f3f3f3f;
    for(int i=1;i<n;i++)
    {
        maxx=max(maxx,arr[i]-minn);
        minn=min(arr[i],minn);
    }
    cout << maxx << endl;
    return 0;
}