Problem:
MathJax.Hub.Config({ tex2jax: { inlineMath: [["$","$"], ["\\(","\\)"]], processEscapes: true }});

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>
#include <stdlib.h>
int main(){
  int input[2], keep, i, j, n, max;
  scanf("%d",&n);
  //  input = (int *)malloc(sizeof(int) * n);
  for(i=0; i<n; i++){
    if(i == 0){
      scanf("%d",&input[0]);
      continue;
    }
    if(i == 1){
      scanf("%d",&input[1]);  
      max = input[1] - input[0];
      continue;
    }
    scanf("%d",&keep);
    if(input[0] > input[1])
      input[0] = input[1];
    input[1] = keep;
      if(input[1]-input[0] > max)
	max = input[1]-input[0];
  }
  printf("%d\n",max);
  return 0;
}