poj2395
krustra最小生成树
View Code
#include
<
iostream
>
#include
<
cstdio
>
#include
<
cstdlib
>
#include
<
cstring
>
#include
<
algorithm
>
using
namespace
std;
#define
maxm 10005
#define
maxn 2005
struct
Edge
{
int
a, b, l;
}edge[maxm];
int
father[maxn];
int
n, m;
bool
operator
<
(
const
Edge
&
a,
const
Edge
&
b)
{
return
a.l
<
b.l;
}
int
getanc(
int
a)
{
if
(a
==
father[a])
return
a;
return
father[a]
=
getanc(father[a]);
}
bool
connected(
int
a,
int
b)
{
if
(getanc(a)
==
getanc(b))
return
true
;
return
false
;
}
void
merge(
int
a,
int
b)
{
father[getanc(a)]
=
getanc(b);
}
int
main()
{
//
freopen("t.txt", "r", stdin);
scanf(
"
%d%d
"
,
&
n,
&
m);
for
(
int
i
=
0
; i
<
n; i
++
)
father[i]
=
i;
for
(
int
i
=
0
; i
<
m; i
++
)
{
scanf(
"
%d%d%d
"
,
&
edge[i].a,
&
edge[i].b,
&
edge[i].l);
edge[i].a
--
;
edge[i].b
--
;
}
sort(edge, edge
+
m);
int
tot
=
0
;
int
ans
=
0
;
int
i
=
0
;
while
(tot
<
n
-
1
)
{
while
(i
<
m
&&
connected(edge[i].a, edge[i].b))
i
++
;
if
(i
>=
m)
break
;
merge(edge[i].a, edge[i].b);
if
(ans
<
edge[i].l)
ans
=
edge[i].l;
tot
++
;
}
printf(
"
%d\n
"
, ans);
return
0
;
}