Compilare: user.cpp:16:6: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type] main(){ ^ user.cpp: In function ‘int main()’: user.cpp:37:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j<cost[p[nod]].size();j++) { ^ user.cpp:44:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j<a[nod].size();j++) { ^