Compilare: user.cpp: In function ‘void DFS(int, int)’: user.cpp:15:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<v[k].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:35:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<VV[k].size(); ++i) { ^ user.cpp:20:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("import.in", "r", stdin); ^ user.cpp:21:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("import.out", "w", stdout); ^ user.cpp:22:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d%d", &n, &m, &K); ^ user.cpp:23:49: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (i=1; i<n; ++i) { scanf ("%d%d", &x, &y); v[x].push_back(y); v[y].push_back(x); } ^ user.cpp:26:46: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d%d%d", &x, &y, &cost, &T); ^