Compilare: user.cpp: In function ‘void dfs1(int)’: user.cpp:20:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<m[x].size();++i) { ^ user.cpp: In function ‘bool find_roots(int)’: user.cpp:32:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<m[x].size();++i) { ^ user.cpp: In function ‘void hashy(int)’: user.cpp:49:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<m[x].size();++i) { ^ user.cpp: In function ‘void dfs2(int, int)’: user.cpp:69:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<m[x].size();++i) { ^ user.cpp: In function ‘void dfs3(int, int)’: user.cpp:84:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<m[x].size();++i) { ^ user.cpp: In function ‘void find_middles(int)’: user.cpp:98:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<tree.size();++i) { ^ user.cpp: In function ‘int main()’: user.cpp:141:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<roots.size();++i) { ^ user.cpp:144:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<v[roots[i]].size();++j) { ^ user.cpp:149:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<roots.size();++i) { ^ user.cpp:151:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<v[roots[i]].size();++j) { ^ user.cpp:114:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("divizori2.in","r",stdin); ^ user.cpp:115:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("divizori2.out","w",stdout); ^ user.cpp:117:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&N); ^ user.cpp:123:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^