class Solution {
public int solution(int a, int d, boolean[] included) {
int answer = 0;
int[] arr = new int[included.length];
arr[0] = a;
for(int i = 0; i < included.length; i++){
if( i >= 1) {
arr[i] = arr[i - 1] + d;
}
if(included[i]){
answer += arr[i];
}
}
return answer;
}
}