Compilare: user.cpp: In function ‘bool dfs(int)’: user.cpp:19:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < v[x].size(); j++) ^ user.cpp:27:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < v[x].size(); j++) ^ user.cpp: In function ‘int main()’: user.cpp:40:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("senat.out", "w", stdout); ^ user.cpp:41:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d\n", &n, &m); ^ user.cpp:44:26: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(s, 4000, f); ^