public class Solution {

public int NumberOfArithmeticSlices(int[] A) {

if(A.Length == 0 || A.Length == 1 || A.Length == 2) return 0;

int [] c = new int[A.Length];

int [] b = new int[A.Length];

c[0] = 0;

c[1] = 0;

b[0] = 0;

b[1] = 0;

for(int i = 2; i < A.Length; i++)

{

if((A[i]- A[i-1]) == (A[i-1]- A[i-2]))

{

b[i] = b[i-1] + 1;

c[i] = c[i-1] + b[i];

}

else{

c[i] = c[i-1];

b[i] = 0;

}

```
}
return c[A.Length -1];
}
```

}