/in/foo.cc: In function 'int main()':
/in/foo.cc:5:19: warning: unused variable 'k' [-Wunused-variable]
  register int i,j,k,n,x1,m,sa,sb,fmin,smin,seatb,seata,pfmin,psmin,p,ans,preans,citynum;
                   ^
/in/foo.cc:5:28: warning: unused variable 'sa' [-Wunused-variable]
  register int i,j,k,n,x1,m,sa,sb,fmin,smin,seatb,seata,pfmin,psmin,p,ans,preans,citynum;
                            ^~
/in/foo.cc:5:31: warning: unused variable 'sb' [-Wunused-variable]
  register int i,j,k,n,x1,m,sa,sb,fmin,smin,seatb,seata,pfmin,psmin,p,ans,preans,citynum;
                               ^~
/in/foo.cc:10:11: warning: 'm' may be used uninitialized in this function [-Wmaybe-uninitialized]
  for(i=1;i<=m;i++) cin>>s[i]>>x[i];
          ~^~~
/in/foo.cc:60:15: warning: 'citynum' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<citynum;  
               ^
/in/foo.cc:51:15: warning: 'smin' may be used uninitialized in this function [-Wmaybe-uninitialized]
   pans[i]=smin/fmin;
           ~~~~^~~~~
/in/foo.cc:5:34: warning: 'fmin' may be used uninitialized in this function [-Wmaybe-uninitialized]
  register int i,j,k,n,x1,m,sa,sb,fmin,smin,seatb,seata,pfmin,psmin,p,ans,preans,citynum;
                                  ^~~~
/in/foo.cc:39:51: warning: 'p' may be used uninitialized in this function [-Wmaybe-uninitialized]
   for(j=i+1;(h[i]-h[j]<0?h[j]-h[i]:h[i]-h[j])<=x1 && j<=p;j++){
             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~