Compilare: user.cpp: In function ‘void read()’: user.cpp:16:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<a.size(); i++) ^ user.cpp: In function ‘void solve()’: user.cpp:40:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=1,j,mx,m; i<x.size(); x[i]=1+mx,i++) ^ user.cpp:40:23: warning: unused variable ‘m’ [-Wunused-variable] for (int i=1,j,mx,m; i<x.size(); x[i]=1+mx,i++) ^ user.cpp:47:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=1; i<x.size(); i++) ^ user.cpp: At global scope: user.cpp:59:6: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type] main() ^