Compilare: user.cpp: In function ‘void BFS(int)’: user.cpp:65:29: 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:99:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("unlock.in","r",stdin); ^ user.cpp:100:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("unlock.out","w",stdout); ^ user.cpp:101:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&T); ^ user.cpp:105:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&n,&m,&k); ^ user.cpp:110:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&a[i][j]); ^