Compilare: user.cpp: In function ‘bool dfs(int, int)’: user.cpp:22:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int u=0;u<g[v].size();++u) ^ user.cpp: In function ‘int main()’: user.cpp:40:33: 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:41:35: 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); ^