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 argc, char const *argv[]) {
  int i,j,N;
  int R[2000000];
  int maxv=-1000000000,minv;

  scanf("%d", &N);

  for (i = 0; i < N; i++) {
    /* code */
    scanf("%d", &R[i]);
  }

  minv=R[0];

    for (j = 1; j <= N-1; j++) {
      /* code */
          if(maxv < R[j]-minv){
            maxv=R[j]-minv;
          }
          if (minv>R[j]) {
            /* code */
            minv=R[j];
          }
    }


  printf("%d\n", maxv);
  return 0;
}