answer.code: In function ‘void query(int, int)’:
answer.code:18:24: error: return-statement with a value, in function returning ‘void’ [-fpermissive]
   18 |     if(a[x][y]) return 0;
      |                        ^
answer.code: In function ‘int main()’:
answer.code:29:10: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   29 |     scanf("%d",&t);
      |     ~~~~~^~~~~~~~~
answer.code:33:14: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   33 |         scanf("%d%d%d",&n,&m,&q);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~
answer.code:37:18: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   37 |             scanf("%d%d",&x,&y);
      |             ~~~~~^~~~~~~~~~~~~~