C++ || O(1) Space || O(N) Time || 10 lines easy approach
Code\n\nclass Solution {\npublic:\n    string decodeCiphertext(string eT, int rows) {\n        int n=eT.size();\n        int col=n/rows;\n        string s="";\n
# Code\n```\nclass Solution {\npublic:\n    string decodeCiphertext(string eT, int rows) {\n        int n=eT.size();\n        int col=n/rows;\n        string s="";\n        for(int i=0;i<col;i++){\n            int j=i;\n            while(j<n){\n                s+=eT[j];\n                j=j+col+1;\n            }\n        }\n        while(isspace(s.back())){\n            s.pop_back();\n        }\n        return s;\n    }\n};\n```
['String', 'C++']