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: Time Limit Exceeded)

#include<stdio.h>
#include<stdlib.h>

int main(){
   int i = 0;
   int j = 0;
   int *data;
   int min = 0;
   int max = 0;
   int num = 0;
   int count = 0;

   while(1){
      scanf("%d",&num);
      if(num >= 2 && num <= 200000){
        break;
      }
   }

data = (int *)malloc(sizeof(int)*num);

   for(i = 0 ; i < num ; i++){
      while(1){
      scanf("%d",&data[i]);
      if(data[i] >= 2 && data[i] <= 1000000000){
        break;
      }
      }
    }

for(i = 1 ; i < num ; i++){
  if(data[i - 1] < data[i]){
    min = data[i - 1];
    break;
  }
  count++;
}

 for(j = count ; j < num ; j++){
   if(data[j -1] < data[j]){
     max = data[j];
   }
 }

 printf("%d\n",max - min);
 return 0;
}