easy c# solution!!!
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```csharp []\nusing System.Text.RegularExpressions;\npublic class Solution {\n    public string DecodeCiphertext(string encodedText, int rows) {\n     if (rows == 1) return encodedText;\n        \n        int length = encodedText.Length;\n        int cols = length / rows;\n        StringBuilder decrypted = new StringBuilder();\n\n        \n        for (int i = 0; i < cols; i++) {\n            for (int j = i; j < length; j += cols + 1) {\n                decrypted.Append(encodedText[j]);\n            }\n        }\n\n        \n        int lastNonSpaceIndex = decrypted.Length - 1;\n        while (lastNonSpaceIndex >= 0 && decrypted[lastNonSpaceIndex] == \' \') {\n            lastNonSpaceIndex--;\n        }\n\n        return decrypted.ToString(0, lastNonSpaceIndex + 1);\n    }\n}\n```
['C#']