very easy beginner friendly solution using common sense
IntuitionApproachComplexity
Time complexity:

Space complexity:
Code
# Intuition
<!-- Describe your first thoughts on how to solve this problem. -->

# Approach
<!-- Describe your approach to solving the problem. -->

# Complexity
- Time complexity:
<!-- Add your time complexity here, e.g. $$O(n)$$ -->

- Space complexity:
<!-- Add your space complexity here, e.g. $$O(n)$$ -->

# Code
```java []
class Solution {
    public long countAlternatingSubarrays(int[] nums) {
        int j=1;
        long count =0;
        long ans=0;
        for(int i=0;i<nums.length-1;i++){
             if(nums[j]==nums[i]){
               ans+= count*(count+1)/2;
               count=0; 
             }
             else{
              count++;
             }
          j++;
        }
        if(count>0){
              ans+= count*(count+1)/2;
        }
        return ans+nums.length;
    }
}
```
['Java']