Compilare: user.cpp: In function ‘int bellmanfordBFS(int)’: user.cpp:28:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<G[x].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:40:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bellmanford.in", "r", stdin); ^ user.cpp:41:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bellmanford.out","w", stdout); ^ user.cpp:43:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:45:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &x, &y, &c); ^