Compilare: user.cpp: In function ‘int main()’: user.cpp:42:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[r].size();i++) ^ user.cpp:53:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[n-1].size();i++) ^ user.cpp:76:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[0].size();i++) ^ user.cpp:16:38: 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:17:40: 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:18:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:21:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&a,&b,&c); ^