✅✅✅ Fast Java Solution || Runtime 💯✅ || Beginners Friendly
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```\nclass Solution {\n    public int[] separateDigits(int[] nums) {\n        int len = 0;\n        for (int num : nums) {\n            while (num > 0) {\n                num /= 10;\n                ++len;\n            }\n        }\n\n        int[] res = new int[len];\n        int index = len-1;\n\n        for (int i = nums.length-1; i >= 0; i--) {\n            int num = nums[i];\n            while (num > 0) {\n                res[index--] = num%10;\n                num /= 10;\n            }\n        }\n\n        return res;\n    }\n}\n```
['Java']