minerals.cpp: In function 'int solve(std::vector<int>, std::vector<int>, int)':
minerals.cpp:22:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
22 | for(int i=0; i<a.size(); i++){
| ~^~~~~~~~~
minerals.cpp:27:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
27 | for (int i=0; i<b.size(); i++){
| ~^~~~~~~~~
minerals.cpp:30:12: warning: init-statement in selection statements only available with '-std=c++17' or '-std=gnu++17'
30 | else if ((diff (b[i])) b1.push_back(b[i]);
| ^
minerals.cpp:30:25: error: expected ';' before 'b1'
30 | else if ((diff (b[i])) b1.push_back(b[i]);
| ^~~
| ;
minerals.cpp:31:3: error: expected primary-expression before 'else'
31 | else b2.push_back(b[i]);
| ^~~~
minerals.cpp:30:45: error: expected ')' before 'else'
30 | else if ((diff (b[i])) b1.push_back(b[i]);
| ~ ^
| )
31 | else b2.push_back(b[i]);
| ~~~~
minerals.cpp:21:15: warning: control reaches end of non-void function [-Wreturn-type]
21 | vector <int> a1, a2, b1, b2;
| ^~