Compilare: user.cpp: In function ‘int hopcroft(int)’: user.cpp:17:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<v[x].size();i++) { ^ user.cpp:25:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<v[x].size();i++) { ^ user.cpp: In function ‘int main()’: user.cpp:44:13: warning: unused variable ‘l’ [-Wunused-variable] int i,j,l; ^ user.cpp:45:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("album.in","r",stdin); ^ user.cpp:46:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("album.out","w",stdout); ^ user.cpp:47:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&k); ^ user.cpp:50:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&p[i][j]); ^