Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:17:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<v[node].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:47:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<vv[node].size(); ++j) ^ user.cpp:59:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<ans.size(); ++i) ^ user.cpp:24:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("marvel.in", "r", stdin); ^ user.cpp:25:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("marvel.out", "w", stdout); ^ user.cpp:27:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &n, &m, &p, &p); ^ user.cpp:29:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &I[i]); ^ user.cpp:31:43: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(i=1; i<=p; ++i) scanf("%d", &P[i]); ^ user.cpp:35:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^