lightningrod.cpp: In function 'int main()':
lightningrod.cpp:19:11: error: 'stk' was not declared in this scope; did you mean 'std'?
19 | while(!stk.empty())
| ^~~
| std
lightningrod.cpp:9:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
9 | scanf(" %d",&n);
| ~~~~~^~~~~~~~~~
lightningrod.cpp:13:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
13 | scanf(" %d %d",&x,&y);
| ~~~~~^~~~~~~~~~~~~~~~