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>

int main (void){
  int d,i,s;
  int saidai,hikaku,saisyou;
  int a[200000];
  i=0;
  saidai=-10000000000;
  saisyou=6000000;
 scanf("%d",&d);
  while(d>i){
    scanf("%d",&a[i]);
    i++;
  }
  saisyou=a[0];
  for(i=0;i<d;i++){
    while(a[i]>saisyou){
      i++;
    }
saisyou=a[i];
    for( s=d-1;s>i;s--){
      hikaku=a[s]-a[i];
      if(hikaku>saidai){
	saidai=hikaku;
     }
    }
  }
 printf("%d\n",saidai);
  return 0;
}