Compilare: user.cpp: In function ‘int main()’: user.cpp:33:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<lvl[i].size();j++) ^ user.cpp:40:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<fth[i].size();j++) ^ user.cpp:44:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<lvl[lv].size();i++) ^ user.cpp:51:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<sons[nd].size();j++) ^ user.cpp:11:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pm2.in","r",stdin); ^ user.cpp:12:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pm2.out","w",stdout); ^ user.cpp:13:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:14:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(i=1;i<=n;i++) scanf("%d",&val[i]); ^ user.cpp:17:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&m); ^ user.cpp:20:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x); ^