运行 ID: 75361

Main.cc: In function ‘int a(int, int)’:
Main.cc:7:8: error: ‘mn’ was not declared in this scope
     if(mn>0) return a(m-1,a(m,n-1));
        ^~
Main.cc:7:8: note: suggested alternative: ‘m’
     if(mn>0) return a(m-1,a(m,n-1));
        ^~
        m
Main.cc:8:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^