/* Challange Number trouble Level : intermediate/Hard Write a program that takes 3 inputs, the first and second will be array and the last input will be an integer. The first array will take the list of numbers and the second one will take list of arithmetic operators Your task is to create a combination of number array and arithmetic array in such way that match to the third input. For Example Input [1,2,3] [+,-,*,/] 5 Output [3*2-1] [3+2/1] Note : repetation of number and operators are not allowed. */ #include #include #include #include #include using namespace std; constexpr const int Target {5}; auto build_expr(vector nv, vector const& ops) { stringstream ss; vector eve; do { for(size_t i{0}; i < ops.size(); ++i) for(size_t j{0}; j < ops.size(); ++j) if(i != j) { stringstream st; st << nv[0] << ops[i] << nv[1] << ops[j] << nv[2]; eve.emplace_back(st.str()); ss << "ofs << " << st.str() << " << " <<"\'\\n\';"<<"\n"; } } while(next_permutation(begin(nv),end(nv))); return pair{ss.str(), eve}; } auto eval = [](auto const& exprs){ string program = R"( #include #include using namespace std; int main() { ofstream ofs("res.txt"); cout << '\n';)"; program += exprs.first + "\n"; program += "ofs.close();\n"; program += "}\n"; ofstream out( "abc.cpp" ); out << program; out.close(); system( "g++ -o abc abc.cpp" ); system( "./abc" ); // read the results back and verify with // Target value ifstream ifs("res.txt"); int tmp, id{0}; while(ifs >> tmp) { if(tmp == Target) cout << exprs.second[id] << " = " << Target << '\n'; ++id; } }; int main() { vector n { 1, 2, 3 }; vector ops {'+', '-', '*', '/'}; eval(build_expr(n, ops)); }

[Challenge] number_trouble.cpp