Compilare: main.cpp: In function 'bool bfs()': main.cpp:30:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<arcs[current_node].size(); ++i) { ~^~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:63:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<arcs[n].size(); ++j) { ~^~~~~~~~~~~~~~~ main.cpp:46:35: 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); ^ main.cpp:47:37: 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); ^ main.cpp:50:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ main.cpp:56:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &a, &b, &c); ^