Compilare: user.cpp: In function ‘int main()’: user.cpp:32:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v.size();++i) ^ user.cpp:33:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<o.size();++j) ^ user.cpp:35:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i1=0;i1<v.size()-1;++i1) ^ user.cpp:36:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i2=i1+1;i2<v.size();++i2) ^ user.cpp:39:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<o.size();++j) ^ user.cpp: In function ‘int dist(int, std::pair<int, int>)’: user.cpp:22:1: warning: control reaches end of non-void function [-Wreturn-type] } ^