Maximum Profit

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 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.

Output
Print the maximum value in a line.

Constraints
2≤n≤200,000
1≤Rt≤109
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

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#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;

int main() {
    int n, t;
    int maxi, mini;
    scanf("%d", &n);
    scanf("%d", &t);
    maxi = -1000000001; mini = t;
    for (int i = 1; i < n; i++) {
        scanf("%d", &t);
        // 先更新当前的最大值
        maxi = maxi < t - mini ? t - mini : maxi;
        // 再更新当前最小值
        mini= mini > t ? t : mini;
    }
    printf("%d\n", maxi);
}