Compilare: user.cpp: In function ‘int dfs(int, int)’: user.cpp:34:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < V[node].size(); ++ i) ^ user.cpp: In function ‘void solve()’: user.cpp:60:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < vis.size(); ++ j) ^ user.cpp: In function ‘void read()’: user.cpp:16:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("andrei.in", "r", stdin); ^ user.cpp:17:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:20:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &x, &y, &z); ^ user.cpp: In function ‘void write()’: user.cpp:70:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("andrei.out", "w", stdout); ^