[BZOJ2330][SCOI2011]糖果

#include <cstdio>
#include <queue>
using namespace std;
typedef long long ll;
const int N=1000010;
const int INF=1<<28;
ll   ans;
int  n,k,S,cnt;
int  head
,maxw
,tim
;
bool inq
;

struct Edge{
int v,w,next;

Edge() {}
Edge(int v,int w,int next):v(v),w(w),next(next) {}
}E
;

void addedge(int u,int v,int w){
E[++cnt]=Edge(v,w,head[u]);
head[u]=cnt;
}

void SPFA(){
queue<int> Q;
maxw[S]=1;
for(int i=1;i<=n;i++) maxw[i]=-INF;
Q.push(S);inq[S]=1;
while(!Q.empty()){
int x=Q.front();
Q.pop();inq[x]=0;
for(int i=head[x];i;i=E[i].next){
Edge e=E[i];
if(maxw[x]+e.w<=maxw[e.v]) continue;
if(++tim[e.v]>n){
printf("-1\n");
return ;
}
maxw[e.v]=maxw[x]+e.w;
if(!inq[e.v]){inq[e.v]=1;Q.push(e.v);}
}
}
for(int i=1;i<=n;i++) ans+=maxw[i];
printf("%lld\n",ans);
}

int main(){
scanf("%d%d",&n,&k);
S=n+1;
for(int i=n;i>=1;i--) addedge(S,i,0);
for(int i=1;i<=k;i++){
int x,a,b;
scanf("%d%d%d",&x,&a,&b);
if(x==1){addedge(a,b,0);addedge(b,a,0);}
else if(x==2) addedge(a,b,1);
else if(x==3) addedge(b,a,0);
else if(x==4) addedge(b,a,1);
else addedge(a,b,0);
}
SPFA();

return 0;
}