Using ArrayList
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 boolean areAlmostEqual(String s1, String s2) {\n        if(s1.equals(s2))\n        return true;\n        ArrayList<Character> ts=new ArrayList<>();\n        ArrayList<Character> ts1=new ArrayList<>();\n        int count=0;\n        for(int i=0;i<s1.length();i++){\n            if(s1.charAt(i)!=s2.charAt(i)){\n            ts.add(s1.charAt(i));\n            ts1.add(s2.charAt(i));    \n        }\n        }\n        for(Character co:ts){\n            if(!(ts1.contains(co)))\n            return false;\n        }\n        return (ts.size()==2 && ts1.size()==2)?true:false;\n    }\n}\n```
['Hash Table', 'Java']