Compilare: user.cpp: In function ‘int BFS()’: user.cpp:25:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < G[node].size(); ++j) ^ user.cpp: In function ‘int main()’: user.cpp:52:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < G[N].size(); ++i) ^ user.cpp:39:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("maxflow.in", "r", stdin); ^ user.cpp:40:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("maxflow.out", "w", stdout); ^ user.cpp:42:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &M); ^ user.cpp:45:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &x, &y, &z); ^