Compilare: user.cpp: In function ‘bool pairup(int)’: user.cpp:17:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0;i < V[nod].size(); ++i) { ^ user.cpp: In function ‘void dfs(int, bool)’: user.cpp:33:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < V[nod].size(); ++i) { ^ user.cpp:42:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < G[nod].size(); ++i) { ^ user.cpp: In function ‘int main()’: user.cpp:53:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("paznici.in", "r", stdin); ^ user.cpp:54:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("paznici.out", "w", stdout); ^ user.cpp:55:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d\n", &n, &m); ^ user.cpp:59:29: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(buffer, Nmax, stdin); ^