Compilare: user.cpp: In function ‘int main()’: user.cpp:24:27: warning: suggest parentheses around comparison in operand of ‘&’ [-Wparentheses] if(mask&(1<<i)==0) ^ user.cpp:28:43: warning: suggest parentheses around comparison in operand of ‘&’ [-Wparentheses] if(mask&(1<<v[i][j].first)==0) ^ user.cpp:11:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("hamilton.in","r",stdin); ^ user.cpp:12:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("hamilton.out","w",stdout); ^ user.cpp:13:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&m); ^ user.cpp:16:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] v[y].push_back(make_pair(x,z)); ^