coins.cpp: In function 'std::vector<int> coin_flips(std::vector<int>, int)':
coins.cpp:20:13: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
20 | for(ll i=0;i<b.size();i++)
| ~^~~~~~~~~
coins.cpp:28:1: warning: no return statement in function returning non-void [-Wreturn-type]
28 | }
| ^
coins.cpp: In function 'int find_coin(std::vector<int>)':
coins.cpp:31:13: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
31 | for(ll i=0;i<b.size();i++)
| ~^~~~~~~~~