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)

#include <iostream>
using namespace std;

const int INF = 2000000000;
int n;
int res;

int main(){
    int temp;
    int minC = INF;
    int maxP = -INF;

    //freopen("D:\\zhouyu\\study\\codes\\MaximumProfit.txt", "r", stdin);
    cin >> n;
    for(int i=0; i<n; i++){
        cin >> temp;
        if(maxP < (temp-minC)){
            maxP = temp-minC;
        }
        if(minC > temp) {
            minC = temp;
        }
    }
    cout << maxP << endl;
}