Compilare: user.cpp: In function ‘void BFS(int, int)’: user.cpp:37:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<v[x].size(); ++i) ^ user.cpp: In function ‘void init()’: user.cpp:59:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<v[o].size(); ++i) ^ user.cpp: In function ‘int BF()’: user.cpp:81:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<G[x].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:119:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<v[o].size(); ++i) ^ user.cpp:140:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<v[L[i]].size(); ++j) ^ user.cpp:103:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("atac2.in","r",stdin); ^ user.cpp:104:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("atac2.out","w",stdout); ^ user.cpp:105:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&n,&m,&u,&o); ^ user.cpp:108:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&L[i]); ^ user.cpp:114:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^