发布Pascal题解：

var
  n,i,j:longint;
  ma,su:int64;
  a:array[0..100001,1..2] of longint;
  procedure kp(l,r:longint);
    var
      mid,i,p,j:longint;
    begin
      i:=l;  j:=r;
      mid:=a[(i+j) div 2,1];
      repeat
        while a[i,1]<mid do inc(i);
        while a[j,1]>mid do dec(j);
        if j>=i then
          begin
            p:=a[i,1];  a[i,1]:=a[j,1];  a[j,1]:=p;
            p:=a[i,2];  a[i,2]:=a[j,2];  a[j,2]:=p;
            inc(i);  dec(j);
          end;
      until i>j;
      if i<r then kp(i,r);
      if l<j then kp(l,j);
    end;
begin
  su:=0;
  fillchar(a,sizeof(a),0);
  a[0,2]:=-1;
  readln(n);
  a[n+1,2]:=-1;
  for i:=1 to n do
    readln(a[i,2],a[i,1]);
  kp(1,n);
  i:=1;  j:=n;
  while i<=j do
    begin
      while a[i,2]=0 do inc(i);
      while a[j,2]=0 do dec(j);
      ma:=a[i,1]+a[j,1];
      if ma>su then su:=ma;
      if a[i,2]>a[j,2] then
        begin
          a[i,2]:=a[i,2]-a[j,2];
          dec(j);
        end
      else
        begin
          a[j,2]:=a[j,2]-a[i,2];
          inc(i);
        end;
    end;
  writeln(su);
end.