foo.cc: In function 'int main()':
foo.cc:68:8: warning: unused variable 'y' [-Wunused-variable]
   68 |  int x,y;
      |        ^
foo.cc:57:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   57 |  scanf("%d%d",&n,&g);
      |  ~~~~~^~~~~~~~~~~~~~
foo.cc:61:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   61 |   scanf("%s",c);
      |   ~~~~~^~~~~~~~
foo.cc:56:9: warning: iteration 20 invokes undefined behavior [-Waggressive-loop-optimizations]
   56 |   vis[i]=1;
      |   ~~~~~~^~
foo.cc:55:15: note: within this loop
   55 |  for(int i=0;i<=20;i++)
      |              ~^~~~
foo.cc:70:3: warning: 'x' may be used uninitialized in this function [-Wmaybe-uninitialized]
   70 |   if((a[1]|a[i])==x)
      |   ^~

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