NKRACING - Vòng đua F1

Tác giả: RR

Ngôn ngữ: Pascal

//Wishing myself a happy lunar new year with a lot of accept solutions
//Written by Nguyen Thanh Trung
{$R-,Q-}
const
  FINP='';
  FOUT='';
  MAXN=10000;
  MAXM=100000;
var
  m,n,sum,mst:longint;
  eu,ev,ec:array[1..MAXM] of longint;
  father:array[1..MAXN] of longint;
procedure inp; inline;
var
  f:text;
  i:longint;
begin
  assign(f,FINP); reset(f);
  read(f,n,m);
  for i:=1 to m do
    read(f,eu[i],ev[i],ec[i]);
  sum:=0;
  for i:=1 to m do inc(sum,ec[i]);
  close(f);
end;
procedure ans; inline;
var
  f:text;
begin
  assign(f,FOUT); rewrite(f);
  writeln(f,sum-mst);
  close(f);
end;
procedure swap(var a,b:longint); inline;
var
  temp:longint;
begin
  temp:=a; a:=b; b:=temp;
end;
procedure sort(l,r:longint); inline;
var
  i,j,mid:longint;
begin
  i:=l; j:=r; mid:=ec[i+random(j-i+1)];
  repeat
    while ec[i]>mid do inc(i);
    while ec[j]<mid do dec(j);
    if i<=j then
      begin
        swap(eu[i],eu[j]);
        swap(ev[i],ev[j]);
        swap(ec[i],ec[j]);
        inc(i); dec(j);
      end;
  until i>j;
  if i<r then sort(i,r);
  if l<j then sort(l,j);
end;
function getRoot(u:longint):longint; inline;
begin
  if father[u]<0 then getRoot:=u
  else begin father[u]:=getRoot(father[u]); getRoot:=father[u]; end;
end;
procedure union(r1,r2:longint); inline;
begin
  if father[r1]<father[r2] then
    begin
      father[r1]:=father[r1]+father[r2];
      father[r2]:=r1;
    end
  else
    begin
      father[r2]:=father[r1]+father[r2];
      father[r1]:=r2;
    end;
end;
procedure solve; inline;
var
  i,sc,u,v,r1,r2:longint;
begin
  for i:=1 to n do father[i]:=-1;
  sort(1,m); sc:=0; mst:=0;
  for i:=1 to m do
    begin
      u:=eu[i]; v:=ev[i];
      r1:=getRoot(u);
      r2:=getRoot(v);
      if r1=r2 then continue;
      union(r1,r2);
      inc(sc); inc(mst,ec[i]);
      if sc=n-1 then break;
    end;
end;
begin
  inp;
  solve;
  ans;
end.

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