stations.cpp: In function 'void dfs(int, int)':
stations.cpp:14:8: warning: left operand of comma operator has no effect [-Wunused-value]
14 | debug("dfs %d\n",x);
| ^~~~~~~~~~
stations.cpp: In function 'std::vector<int> label(int, int, std::vector<int>, std::vector<int>)':
stations.cpp:44:9: warning: left operand of comma operator has no effect [-Wunused-value]
44 | debug("%d ",i);
| ^~~~~
stations.cpp:45:8: warning: statement has no effect [-Wunused-value]
45 | debug("\n");
| ~^~~~~
stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:62:8: warning: left operand of comma operator has no effect [-Wunused-value]
62 | debug("qr %d %d ~",s,t); for(int i : c) debug("%d ",i); debug("\n");
| ^~~~~~~~~~~~
stations.cpp:62:23: warning: right operand of comma operator has no effect [-Wunused-value]
62 | debug("qr %d %d ~",s,t); for(int i : c) debug("%d ",i); debug("\n");
| ^
stations.cpp:62:48: warning: left operand of comma operator has no effect [-Wunused-value]
62 | debug("qr %d %d ~",s,t); for(int i : c) debug("%d ",i); debug("\n");
| ^~~~~
stations.cpp:62:64: warning: statement has no effect [-Wunused-value]
62 | debug("qr %d %d ~",s,t); for(int i : c) debug("%d ",i); debug("\n");
| ~^~~~~
stations.cpp:70:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
70 | for(int i=0;i<c.size();i++){
| ~^~~~~~~~~
stations.cpp:81:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
81 | for(int i=1;i<c.size()-1;i++){
| ~^~~~~~~~~~~