[백준] 2847번 : 게임을 만든 동준이 - Java(자바)

https://www.acmicpc.net/problem/2847

import java.util.*;
public class Main {
    public static void main(String args[]) {
        Scanner s=new Scanner(System.in);
        int n=s.nextInt();
        int arr[]=new int[n];
        int count=0;
        for(int i=0;i<n;i++){
            arr[i]=s.nextInt();
        }
        for(int i=n-1;i>0;i--){
            if(arr[i]<=arr[i-1]){
                count+=arr[i-1]-arr[i]+1;
                arr[i-1]=arr[i]-1;
            }
        }
        System.out.print(count);
    }
}