NNN solution with O(n)
Intuition\n Describe your first thoughts on how to solve this problem. \n\n# Approach\n Describe your approach to solving the problem. \n\n# Complexity\n- Time 
# Intuition\n<!-- Describe your first thoughts on how to solve this problem. -->\n\n# Approach\n<!-- Describe your approach to solving the problem. -->\n\n# Complexity\n- Time complexity:\n<!-- Add your time complexity here, e.g. $$O(n)$$ -->\n\n- Space complexity:\n<!-- Add your space complexity here, e.g. $$O(n)$$ -->\n\n# Code\n```java []\nclass Solution {\n    public long countAlternatingSubarrays(int[] nums) {\n        long ans = 0;\n        int j = 0;\n        for(int i = 1 ;i < nums.length;i++){\n            if(nums[i] != nums[i - 1])\n                ans += i - j;\n            else\n                j = i;\n        }\n        return ans + nums.length;\n    }\n}\n```
['Java']