OJ-Problems-Source/HDOJ/1853_autoAC.cpp
2016-08-17 15:13:51 +08:00

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;
}