Compilare: main.cpp: In function 'int main()': main.cpp:17:57: warning: comparison of integer expressions of different signedness: 'int' and 'const std::__cxx11::basic_string<char>::size_type' {aka 'const long unsigned int'} [-Wsign-compare] 17 | for(int j=0,k;k=s.find(a[i],j),k!=string::npos;b[i][j+a[i].size()]=1,j=k+1); | ~^~~~~~~~~~~~~~ main.cpp:16:29: warning: unused variable 'j' [-Wunused-variable] 16 | for(int i=0,j=0;i<n;++i) | ^