poj 2398 2012-01-11

http://poj.org/problem?id=2398

 

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题目大意：和poj2318一样，只是询问玩具数为x的区间有多少个。

先将区间排序一下，然后二分判断。

 

 

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Program Stone;
var i,n,m,x1,x2,y1,y2,xi,yi:longint;
    ui,li:array[0..10000]of longint;
    ans,tot:array[0..10000]of longint;
 procedure kp(t,w:longint);
 var i,j,k,mid,mi:longint;
  begin
    i:=t;j:=w;mid:=ui[(t+w)div 2];mi:=li[(t+w)div 2];
    repeat
      while (ui[i]<mid)or((ui[i]=mid)and(li[i]<mi)) do inc(i);
      while (ui[j]>mid)or((ui[j]=mid)and(li[j]>mi)) do dec(j);
      if i<=j then begin
                      k:=ui[i];ui[i]:=ui[j];ui[j]:=k;
                      k:=li[i];li[i]:=li[j];li[j]:=k;
                      inc(i);dec(j);
                   end;
    until i>j;
    if i<w then kp(i,w);
    if j>t then kp(t,j);
  end;
 procedure init;
 var i,j,k:longint;
  begin
     readln(n,m,x1,y1,x2,y2);
     ui[0]:=x1;li[0]:=x1;
     ui[n+1]:=x2;li[n+1]:=x2;
     if n=0 then halt;
     for i:=1 to n do readln(ui[i],li[i]);
     kp(1,n);
  end;
 Function cross(x1,y1,x2,y2,x3,y3,x4,y4:longint):longint;
  begin
    cross:=(x2-x1)*(y4-y3)-(y2-y1)*(x4-x3);
  end;
 function ef(x,y:longint):longint;
 var i,j,k,left,right,mid:longint;
  begin
     left:=0;right:=n+1;
     while left+1<right do
      begin
         mid:=(left+right)div 2;
         k:=cross(li[mid],y2,ui[mid],y1,li[mid],y2,x,y);
         if k<0 then left:=mid;
         if k>0 then right:=mid;
      end;
     ef:=left;
  end;
 Procedure print;
 var i:longint;
  begin
    writeln('Box');
    for i:=0 to n do
     inc(tot[ans[i]]);
    for i:=1 to m do
     if tot[i]<>0 then writeln(i,': ',tot[i]);
    fillchar(tot,sizeof(tot),0);
    fillchar(ans,sizeof(ans),0);
  end;
Begin
 assign(input,'input.in');reset(input);
   while true do
    begin
       init;
       for i:=1 to m do
        begin
          readln(xi,yi);
          inc(ans[ef(xi,yi)]);
        end;
       print;
    end;
end.