Compilare: user.cpp: In function ‘int cmp(event, event)’: user.cpp:64:5: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(one.when == two.when) ^ user.cpp: In function ‘void solve()’: user.cpp:113:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < hap.size(); ++i){ ^