Compilare: main.cpp: In function 'std::vector<int> dpmerge(std::vector<int>&, std::vector<int>&)': main.cpp:10:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=v1.size();i++) ~^~~~~~~~~~~ main.cpp:15:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=v2.size();i++) ~^~~~~~~~~~~ main.cpp:20:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=v1.size();i++) ~^~~~~~~~~~~ main.cpp:21:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=1;j<=v2.size();j++) ~^~~~~~~~~~~ main.cpp: In function 'void dfs(int)': main.cpp:43:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[nod].size();i++) dfs(v[nod][i]); ~^~~~~~~~~~~~~~ main.cpp:47:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<v[nod].size();i++) ~^~~~~~~~~~~~~~ main.cpp:49:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<aux.size();i++) d[nod].push_back(aux[i]); ~^~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:54:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("purification.in","r",stdin); ^ main.cpp:55:43: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("purification.out","w",stdout); ^ main.cpp:57:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ main.cpp:58:44: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] for(int i=1;i<=n;i++) scanf("%d",&w[i]); ^ main.cpp:61:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x); ^