foo.cc: In function 'int main()':
foo.cc:68:25: error: expected ';' before ')' token
     mer((i-1)*m+j,i*m+j));
                         ^
foo.cc:71:4: error: expected ';' before '}' token
    }
    ^
foo.cc:76:31: error: expected ';' before ')' token
     mer((i-1)*m+j,(i-1)*m+j+1));
                               ^
foo.cc:79:4: error: expected ';' before '}' token
    }
    ^

自豪的采用 HydroJudger 进行评测(github.com/hydro-dev/HydroJudger)