foo.cc: In function 'int main()':
foo.cc:16:18: warning: unused variable 'n' [-Wunused-variable]
  int m1,n1,m2,n2,n;cin>>m1>>n1>>m2>>n2;
                  ^

自豪的采用jd5进行评测(github.com/masnn/jd5)

{"receive":"2020-02-28T03:23:25.569Z","handle":"2020-02-28T03:23:25.570Z","done":"2020-02-28T03:23:26.346Z"}