[TJOI2010]电影迷

[TJOI2010]电影迷

题目链接：[TJOI2010]电影迷

水题，因为有负权，总体加个正值即可。

AC代码：

#pragma GCC optimize("-Ofast","-funroll-all-loops")
#include<bits/stdc++.h>
//#define int long long
using namespace std;
const int N=110,M=1e6+10;
const int inf=0x3f3f3f3f;
int n,m,s,t,h[N],res,base=2000;
int head[N],nex[M],to[M],w[M],tot=1;
inline void ade(int a,int b,int c){to[++tot]=b; nex[tot]=head[a]; w[tot]=c; head[a]=tot;
}
inline void add(int a,int b,int c){ade(a,b,c);	ade(b,a,0);}
inline int bfs(){queue<int> q;	q.push(s);	memset(h,0,sizeof h); h[s]=1;while(q.size()){int u=q.front();	q.pop();for(int i=head[u];i;i=nex[i]){if(w[i]&&!h[to[i]]){h[to[i]]=h[u]+1;	q.push(to[i]);}}}return h[t];
}
int dfs(int x,int f){if(x==t)	return f;	int fl=0;for(int i=head[x];i&&f;i=nex[i]){if(w[i]&&h[to[i]]==h[x]+1){int mi=dfs(to[i],min(w[i],f));w[i]-=mi,w[i^1]+=mi,fl+=mi,f-=mi;}}if(!fl)	h[x]=-1;return fl;
}
inline int dinic(){int res=0;while(bfs())	res+=dfs(s,inf);return res;
}
signed main(){cin>>n>>m;	t=n+1;for(int i=1,x;i<=n;i++)	cin>>x,add(s,i,x+base),add(i,t,base),res+=x+2*base;for(int i=1,x,y,d;i<=m;i++)	cin>>x>>y>>d,add(x,y,d);res-=dinic();	res-=n*base;cout<<max(res,0);return 0;
}