we calculate the difference between any two consecutive elements and find that for n same difference the total number will be (n-1)+(n-2)+(n-3)...+(1)

```
public class Solution {
public int numberOfArithmeticSlices(int[] A) {
if(A.length==0)return 0;
int [] tabs=new int[A.length-1];
for(int i=1;i<A.length;i++){
tabs[i-1]=A[i]-A[i-1];
}
int ans=0;
int count=1;
for(int i=1;i<tabs.length;i++){
if(tabs[i]==tabs[i-1]){
ans+=count++;
}
else count=1;
}
return ans;
}
}
```