molecules.cpp: In function 'std::vector<int> find_subset(int, int, std::vector<int>)':
molecules.cpp:12:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
12 | for(int i=0;i<w.size();i++)
| ~^~~~~~~~~
molecules.cpp:20:20: error: redeclaration of 'std::vector<int> ans'
20 | vector < int > ans;
| ^~~
molecules.cpp:10:20: note: 'std::vector<int> ans' previously declared here
10 | vector < int > ans;
| ^~~
molecules.cpp:21:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
21 | for(int sum=0,ru=0,lu=0;ru<w.size();ru++)
| ~~^~~~~~~~~