View Compilation Error

0_0_36801783_8819.cpp: In function 'void MAIN::MAIN()':
0_0_36801783_8819.cpp:111:86: error: invalid conversion from 'int' to 'const char*' [-fpermissive]
             for(res i=0;i<sz;i++)add(ret,mul(mul(d[i],pw[pc(i)]),qpow(b[i],strlen(b[i]))));
                                                                                      ^
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/cstring:42:0,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/x86_64-w64-mingw32/bits/stdc++.h:48,
                 from 0_0_36801783_8819.cpp:1:
GCC4.9.2/x86_64-w64-mingw32/include/string.h:54:18: note: initializing argument 1 of 'size_t strlen(const char*)'
   size_t __cdecl strlen(const char *_Str);
                  ^