foo.cc: In function 'int main()':
foo.cc:15:22: error: 'j' was not declared in this scope
       if(a[1][i]==m) j=i+1;
                      ^
foo.cc:18:7: error: 'j' was not declared in this scope
    if(j>n)
       ^
foo.cc:20:14: error: 'j' was not declared in this scope
    a[i][a[i][j]]=k;
              ^

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。