bzoj3632

裸的最大团，随机化大法好

多次随机出一个选择顺序然后贪心即可

 var b:array[..,..] of boolean;
     a:array[..] of longint;
     v:array[..] of boolean;
     n,m,i,j,x,y,ans:longint;

 procedure swap(var a,b:longint);
   var c:longint;
   begin
     c:=a;
     a:=b;
     b:=c;
   end;

 procedure work;
   var i,j,s:longint;
   begin
     s:=;
     fillchar(v,sizeof(v),false);
     for i:= to n do
       if not v[a[i]] then
       begin
         v[a[i]]:=true;
         for j:=i+ to n do
           if not b[a[i],a[j]] then v[a[j]]:=true;
         inc(s);
       end;
     if ans<s then ans:=s;
   end;

 begin
   readln(n);
   while not eof do
   begin
     readln(x,y);
     b[x,y]:=true;
     b[y,x]:=true;
   end;
   for i:= to n do
     a[i]:=i;
   work;
   for i:= to  do
   begin
     for j:= to n do
       swap(a[j],a[trunc(random*j)+]);
     work;
   end;
   writeln(ans);
 end.