Compilare: user.cpp: In function ‘void dfs2(int)’: user.cpp:16:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<m[x].size();++i) { ^ user.cpp: In function ‘int find_root(int, int)’: user.cpp:27:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k=0;k<nodes.size();++k) { ^ user.cpp:33:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<m[n].size();++i) { ^ user.cpp: In function ‘void dfs(int, int)’: user.cpp:63:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<m[x].size();++i) { ^ user.cpp: In function ‘void solve(int, int)’: user.cpp:78:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<nodes.size();++i) { ^ user.cpp:86:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<nodes.size();++i) { ^ user.cpp:90:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<m[A].size();++i) { ^ user.cpp:93:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k=0;k<m[y].size();++k) { ^ user.cpp: In function ‘int main()’: user.cpp:108:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ecotraseu.in","r",stdin); ^ user.cpp:109:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ecotraseu.out","w",stdout); ^ user.cpp:111:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&T); ^ user.cpp:114:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&N); ^ user.cpp:122:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&x,&y,&c); ^