Compilare: user.cpp: In function ‘long long int solve(int, int)’: user.cpp:31:30: warning: variable ‘a2’ set but not used [-Wunused-but-set-variable] long long ans=-1,a2; ^ user.cpp:32:45: warning: unused variable ‘l’ [-Wunused-variable] int i,j,mi=(st+dr)>>1,ls=0,ld=0,l; ^ user.cpp: In function ‘int main()’: user.cpp:73:13: warning: unused variable ‘j’ [-Wunused-variable] int n,i,j; ^ user.cpp:71:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cmap.in","r",stdin); ^ user.cpp:72:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cmap.out","w",stdout); ^ user.cpp:76:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:79:53: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld",&ve[i].first,&ve[i].second); ^