QBMST - Cây khung nhỏ nhất ( HEAP )
Tác giả: flashmt
Ngôn ngữ: Pascal
var n,m,i,j,x,y,re:longint;
a,b,c,d:array[1..15555] of longint;
procedure sort(l,r:longint);
var i,j,x,y:longint;
begin
i:=l; j:=r; x:=c[(i+j) shr 1];
repeat
while c[i]<x do i:=i+1;
while c[j]>x do j:=j-1;
if i<=j then
begin
y:=a[i]; a[i]:=a[j]; a[j]:=y;
y:=b[i]; b[i]:=b[j]; b[j]:=y;
y:=c[i]; c[i]:=c[j]; c[j]:=y;
i:=i+1; j:=j-1;
end;
until i>j;
if i<r then sort(i,r);
if l<j then sort(l,j);
end;
function find(x:longint):longint;
begin
if x<>d[x] then d[x]:=find(d[x]);
exit(d[x]);
end;
begin
read(n,m);
for i:=1 to n do d[i]:=i;
for i:=1 to m do read(a[i],b[i],c[i]);
sort(1,m);
for i:=1 to m do
begin
x:=find(a[i]); y:=find(b[i]);
if x<>y then
begin
d[y]:=x;
dec(n); re:=re+c[i];
if n=1 then
begin
writeln(re); halt;
end;
end;
end;
end.