114 lines
2.7 KiB
C++
114 lines
2.7 KiB
C++
#include<iostream>
|
|
#include<cstdio>
|
|
#include<cstring>
|
|
#include<algorithm>
|
|
#include<climits>
|
|
using namespace std;
|
|
#define N 505
|
|
#define MAXN 1<<28
|
|
int map[N][N];
|
|
int lx[N], ly[N];
|
|
int slack[N];
|
|
int match[N];
|
|
bool visitx[N], visity[N];
|
|
int n;
|
|
bool Hungary(int u)
|
|
{
|
|
visitx[u] = true;
|
|
for(int i = 1; i <= n; ++i)
|
|
{
|
|
if(visity[i])
|
|
continue;
|
|
else
|
|
{
|
|
if(lx[u] + ly[i] == map[u][i])
|
|
{
|
|
visity[i] = true;
|
|
if(match[i] == -1 || Hungary(match[i]))
|
|
{
|
|
match[i] = u;
|
|
return true;
|
|
}
|
|
}
|
|
else
|
|
slack[i] = min(slack[i], lx[u] + ly[i] - map[u][i]);
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
void KM_perfect_match()
|
|
{
|
|
int temp;
|
|
for(int i = 1; i <= n; ++i)
|
|
lx[i] = -MAXN;
|
|
memset(ly, 0, sizeof(ly));
|
|
for(int i = 1; i <= n; ++i)
|
|
for(int j = 1; j <= n; ++j)
|
|
lx[i] = max(lx[i], map[i][j]);
|
|
for(int i = 1; i <= n; ++i)
|
|
{
|
|
for(int j = 1; j <= n; ++j)
|
|
slack[j] = MAXN;
|
|
while(1)
|
|
{
|
|
memset(visitx, false, sizeof(visitx));
|
|
memset(visity, false, sizeof(visity));
|
|
if(Hungary(i))
|
|
break;
|
|
else
|
|
{
|
|
temp = MAXN;
|
|
for(int j = 1; j <= n; ++j)
|
|
if(!visity[j])
|
|
temp = min(temp, slack[j]);
|
|
for(int j = 1; j <= n; ++j)
|
|
{
|
|
if(visitx[j])
|
|
lx[j] -= temp;
|
|
if(visity[j])
|
|
ly[j] += temp;
|
|
else
|
|
slack[j] -= temp;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
int main()
|
|
{
|
|
int m;
|
|
int a, b, cost;
|
|
int ans;
|
|
bool flag;
|
|
while(scanf("%d%d", &n, &m) != EOF)
|
|
{
|
|
ans = 0;
|
|
flag = true;
|
|
memset(match, -1, sizeof(match));
|
|
for(int i = 1; i <= n; ++i)
|
|
for(int j = 1; j <= n; ++j)
|
|
map[i][j] = -MAXN;
|
|
for(int i = 1; i <= m; ++i)
|
|
{
|
|
scanf("%d%d%d", &a, &b, &cost);
|
|
if(-cost > map[a][b])
|
|
map[a][b] = -cost;
|
|
}
|
|
KM_perfect_match();
|
|
for(int i = 1; i <= n; ++i)
|
|
{
|
|
if(match[i] == -1 || map[ match[i] ][i] == -MAXN)
|
|
{
|
|
flag = false;
|
|
break;
|
|
}
|
|
ans += map[match[i]][i];
|
|
}
|
|
if(flag)
|
|
printf("%d\n", -ans);
|
|
else
|
|
printf("-1\n");
|
|
}
|
|
return 0;
|
|
}
|