Problem:
Score : 300 points

Problem Statement

In a flower bed, there are N flowers, numbered 1,2,......,N. Initially, the heights of all flowers are 0.
You are given a sequence h=\{h_1,h_2,h_3,......\} as input. You would like to change the height of Flower k to h_k for all k (1 \leq k \leq N), by repeating the following "watering" operation:

Specify integers l and r. Increase the height of Flower x by 1 for all x such that l \leq x \leq r.

Find the minimum number of watering operations required to satisfy the condition.

Constraints

1 \leq N \leq 100

0 \leq h_i \leq 100

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
h_1 h_2 h_3 ...... h_N

Output

Print the minimum number of watering operations required to satisfy the condition.

Sample Input 1

4
1 2 2 1

Sample Output 1

2

The minimum number of watering operations required is 2.
One way to achieve it is:

Perform the operation with (l,r)=(1,3).

Perform the operation with (l,r)=(2,4).

Sample Input 2

5
3 1 2 3 1

Sample Output 2

5

Sample Input 3

8
4 23 75 0 23 96 50 100

Sample Output 3

221

Solution in C (GCC 5.4.1) (judge verdict: Time Limit Exceeded)

#include <stdio.h>
int main() {
    int N;
    scanf("%d",&N);
    int array[N];
    int count = 0;

    int stop=0;

    for(int i=0;i <= N-1;i++){
        scanf("%d",&array[i]);
    }
 
    
    while(stop == 0){
        int start=-1;
        int end=-1;
        int min=101;

        for (int i=0;i<=N-1;i++){
            if (array[i]!=0&&start==-1){
                start=i;
                min=array[i];
                continue;
            }
            if(start!=-1){
                if(array[i]!=0){
                    if(min<=array[i]){
                    min=array[i];
                }
                }else{
                    end =i-1;
                    break;
                }
            }
      }
        if (start==-1){
            break;
        }
        for (int i=start;i<=end;i++){
            array[i]=array[i]-min;
        }
        count = count+min;
    }

    printf("%d", count);
    
  
    
    return 0;
}