/in/foo.cc: In function 'int main()':
/in/foo.cc:8:18: warning: unused variable 'sum' [-Wunused-variable]
  int num[100000],sum=0;
                  ^~~
/in/foo.cc:14:10: warning: unused variable 'ans' [-Wunused-variable]
  int C,R,ans;
          ^~~
/in/foo.cc:29:16: warning: 'mx' may be used uninitialized in this function [-Wmaybe-uninitialized]
        cout<<mx-lt+1<<endl;
              ~~^~~
/in/foo.cc:29:16: warning: 'lt' may be used uninitialized in this function [-Wmaybe-uninitialized]