stations.cpp: In function 'void dfs(int, int)':
stations.cpp:14:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
14 | for (int i=0; i<v1[a].size(); i++)
| ~^~~~~~~~~~~~~
stations.cpp: In function 'std::vector<int> label(int, int, std::vector<int>, std::vector<int>)':
stations.cpp:42:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
42 | for (int i=0; i<v2.size(); i++)
| ~^~~~~~~~~~
stations.cpp:49:1: error: a function-definition is not allowed here before '{' token
49 | {
| ^
stations.cpp:76:1: error: expected '}' at end of input
76 | }
| ^
stations.cpp:24:78: note: to match this '{'
24 | std::vector<int> label(int n, int k, std::vector<int> u, std::vector<int> v) {
| ^