Compilare: user.cpp: In function ‘void print_graph(long int)’: user.cpp:20:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (long j = 0; j < graph[i].size(); j++) ^ user.cpp: In function ‘void dijkstra(long int, long int)’: user.cpp:65:57: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (long i = 0; i < graph[crt_vert.first].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:78:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dijkstra.in", "r", stdin); ^ user.cpp:79:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dijkstra.out", "w", stdout); ^