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 <stdio.h>

int main() {

    int n,rj,ri,max,tmp,minv;
    int t[200001]={};
    int i,j;

    scanf("%d",&n);

    for(i = 0; i < n; i++){
        scanf("%d",&t[i]);
    }

    max = t[1] - t[0];

    // for(j = 1; j < n; j++){
    //     for(i = 0; i < j; i++){
    //         tmp = t[j] - t[i];
    //         if(tmp > max){
    //             max = tmp;
    //         }
    //     }
    // }

    minv = t[0];

    for(j = 1; j < n; j++){
        tmp = t[j] - minv;
        if (tmp > max) {
            max = tmp;
        }
        if (minv > t[j]) {
            minv = t[j];
        }

    }

    printf("%d\n",max);

    return 0;
}