Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:18:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < con[x].size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:44:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k = 0; k < h[j % HASH].size(); k++) { ^ user.cpp:28:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("autobuze.in", "r", stdin); ^ user.cpp:29:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("autobuze.out", "w", stdout); ^ user.cpp:30:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:33:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a); ^