leetcode

2075.cpp (452B)

 class Solution {
   public:
     string decodeCiphertext(const string &encodedText, int rows) const {
         const int col = size(encodedText) / rows;
         string res;
 
         for (int i = 0; i < col; i++) {
             for (int j = i; j < size(encodedText); j += (col + 1)) {
                 res += encodedText[j];
             }
         }
 
         while (!res.empty() && res.back() == ' ')
             res.pop_back();
 
         return res;
     }
 };