poj1325
最小点集覆盖
匈牙利算法
View Code
#include
<
iostream
>
#include
<
cstdio
>
#include
<
cstdlib
>
#include
<
cstring
>
using
namespace
std;
#define
maxn 105
int
n, uN, vN;
bool
g[maxn][maxn];
int
xM[maxn], yM[maxn];
bool
chk[maxn];
bool
SearchPath(
int
u)
{
int
v;
for
(v
=
0
; v
<
vN; v
++
)
if
(g[u][v]
&&
!
chk[v])
{
chk[v]
=
true
;
if
(yM[v]
==
-
1
||
SearchPath(yM[v]))
{
yM[v]
=
u;
xM[u]
=
v;
return
true
;
}
}
return
false
;
}
int
MaxMatch()
{
int
u, ret
=
0
;
memset(xM,
-
1
,
sizeof
(xM));
memset(yM,
-
1
,
sizeof
(yM));
for
(u
=
0
; u
<
uN; u
++
)
if
(xM[u]
==
-
1
)
{
memset(chk,
false
,
sizeof
(chk));
if
(SearchPath(u))
ret
++
;
}
return
ret;
}
void
input()
{
scanf(
"
%d%d
"
,
&
vN,
&
n);
memset(g,
0
,
sizeof
(g));
for
(
int
i
=
0
; i
<
n; i
++
)
{
int
a, b, c;
scanf(
"
%d%d%d
"
,
&
a,
&
b,
&
c);
if
(b
&&
c)
g[b][c]
=
true
;
}
}
int
main()
{
//
freopen("t.txt", "r", stdin);
while
(scanf(
"
%d
"
,
&
uN), uN)
{
input();
int
ans
=
MaxMatch();
printf(
"
%d\n
"
, ans);
}
return
0
;
}