foo.cc: In function 'int main()':
foo.cc:19:5: warning: this 'while' clause does not guard... [-Wmisleading-indentation]
     while(read(a[++n]));n--;
     ^~~~~
foo.cc:19:25: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'while'
     while(read(a[++n]));n--;
                         ^

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