Easy C# solution
Approach\nFind smallest equal char for every char;\n\n# Complexity\n- Time complexity:O(n*26+m) = O(n+m)\n Add your time complexity here, e.g.  \n\n- Space comp
# Approach\nFind smallest equal char for every char;\n\n# Complexity\n- Time complexity:$$O(n*26+m) = O(n+m)$$\n<!-- Add your time complexity here, e.g.  -->\n\n- Space complexity:$$O(26) = O(1)$$\n<!-- Add your space complexity here, e.g. $$O(n)$$ -->\n\n# Code\n```\npublic class Solution\n{\n    public string SmallestEquivalentString(string s1, string s2, string baseStr)\n    {\n        char[] arr = new char[26];\n        for (ushort i = 0; i < 26; i++) arr[i] = (char)(\'a\' + i);\n        for(int i=0; i<s1.Length; i++)\n        {\n            char min = arr[s1[i]-\'a\'];\n            char max = arr[s2[i]-\'a\'];\n            if(max < min) (max, min) = (min, max);\n            for (int j = 0; j < arr.Length; j++)\n                if (arr[j] == max) arr[j] = min;\n        }\n        return new string(baseStr.Select(x => arr[x - \'a\']).ToArray());\n    }\n}\n```
['C#']