View Compilation Error

0_0_39516721_12623.cpp: In function 'void solve()':
0_0_39516721_12623.cpp:18:53: error: invalid conversion from 'const char*' to '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'} [-fpermissive]
   18 |         for(int i=0;i<=n+2;i++) op[0][i]=op[n+1][i]="#";
      |                                                     ^~~
      |                                                     |
      |                                                     const char*