NOI2002 荒岛野人

这题其实黑书上有，只是我脑残的没想起来……

其实就是拓展欧几里得算法

我参看的题解：http://www.cnblogs.com/Rinyo/archive/2012/11/25/2788373.html

还有一个讲解的很清楚的exgcd：http://www.cnblogs.com/Rinyo/archive/2012/11/25/2787419.html

代码：

 var c,p,l:array[..] of longint;
     ans,now,n,i,j,d,x,y,pp,cc:longint;
     flag:boolean;
 function min(x,y:longint):longint;
  begin
  if x<y then exit(x) else exit(y);
  end;
 function max(x,y:longint):longint;
  begin
  if x>y then exit(x) else exit(y);
  end;
 function exgcd(a,b:longint;var x,y:longint):longint;
  var t,d:longint;
  begin
  if b= then
   begin
   x:=;y:=;exit(a);
   end;
  d:=exgcd(b,a mod b,x,y);
  t:=x;x:=y;y:=t-(a div b)*y;
  exit(d);
  end;
 procedure main;
  begin
  readln(n);
  for i:= to n do
   begin
   readln(c[i],p[i],l[i]);
   ans:=max(ans,c[i]);
   end;
  while true do
   begin
   flag:=true;
   for i:= to n- do
    begin
     for j:=i+ to n do
      begin
      pp:=p[i]-p[j];cc:=c[j]-c[i];
      d:=exgcd(pp,ans,x,y);
      if cc mod d<> then continue;
      now:=x*cc div d;
      now:=now mod (ans div d);
      if now< then inc(now,abs(ans div d));
      if now<=min(l[i],l[j]) then begin flag:=false;break;end;
      end;
     if not(flag) then break;
     end;
   if flag then break;
   inc(ans);
   end;
  writeln(ans);
  end;
 begin
  main;
 end.                         

我要开始刷noi历年题了！我相信我一定能够坚持下来！