POJ 2528（数据有误的线段树）

此题数据有误……

是我英文太差，还是答案出错……

Program P2528;const   maxn=10000;   maxr=10000000;var   t,n,i,j,k:longint;   a,b,v:array[1..maxn*2] of longint;   h:array[1..maxr] of longint;   col:array[1..maxn*100] of longint;   visit:array[1..maxn*2] of boolean;procedure qsort(l,r:longint);var   i,j,m,p:longint;begin   i:=l;   j:=r;   m:=v[(l+r) div 2];   repeat      while v[i]<m do inc(i);      while v[j]>m do dec(j);      if i<=j then      begin         p:=v[i];         v[i]:=v[j];         v[j]:=p;         inc(i);         dec(j);      end;   until i>j;   if l<j then qsort(l,j);   if i<r then qsort(i,r);end;procedure update(l,r,sonl,sonr,root,color:longint);var   i,j,k,mid:longint;begin   mid:=(l+r) shr 1;   if (sonl<=l) and (r<=sonr) then   begin      col[root]:=color;      exit;   end;   if (col[root]>=0) then   begin      col[root*2]:=col[root];      col[root*2+1]:=col[root];      col[root]:=-1;   end;   if not((mid<sonl) or (sonr<l)) then update(l,mid,sonl,sonr,root*2,color);   if not((r<sonl) or (sonr<mid+1)) then update(mid+1,r,sonl,sonr,root*2+1,color);end;function dfs(l,r,root:longint):longint;var   i,j,mid:longint;begin   mid:=(l+r) shr 1;   if col[root]=0 then exit(0);   if col[root]>0 then   begin      if not(visit[col[root]]) then      begin         visit[col[root]]:=true;         exit(1);      end      else exit(0);   end;   exit(dfs(l,mid,root*2)+dfs(mid+1,r,root*2+1));end;begin   read(t);   while t>0 do   begin      dec(t);      read(n);      for i:=1 to n do      begin         read(a[i],b[i]);         v[i]:=a[i];         v[n+i]:=b[i];      end;      qsort(1,2*n);      j:=1;      for i:=2 to 2*n do         if v[i]<>v[i-1] then         begin            inc(j);            v[j]:=v[i];         end;      for i:=1 to j do h[v[i]]:=i;      fillchar(col,sizeof(col),0);      for i:=1 to n do      begin        update(1,j,h[a[i]],h[b[i]],1,i);      end;      fillchar(visit,sizeof(visit),false);      writeln(dfs(1,j,1));   end;end.