度度熊的交易计划
这是一个最小费用最大流的模板题,建边也很直接,唯一需要注意的是当跑出来的费用为正(dist[t]>0)的时候就不要跑了,当时就是这个地方弄错了,还以为我的模板错啦…..
/*Problem : 6118 ( 度度熊的交易计划 ) Judge Status : Accepted
*RunId : 21751738 Language : G++ Author : zouzhitao
*Code Render Status : Rendered By HDOJ G++ Code Render Version 0.01 Beta
*/
#include
#define pb push_back
#define mp make_pair
#define PI acos(-1)
#define fi first
#define se second
#define INF 0x3f3f3f3f
#define INF64 0x3f3f3f3f3f3f3f3f
#define random(a,b) ((a)+rand()%((b)-(a)+1))
#define ms(x,v) memset((x),(v),sizeof(x))
#define scint(x) scanf("%d",&x );
#define scf(x) scanf("%lf",&x );
#define eps 1e-10
#define dcmp(x) (fabs(x) < eps? 0:((x) <0?-1:1))
#define lc o<<1
#define rc o<<1|1
using namespace std;
typedef long long LL;
typedef long double DB;
typedef pair<int,int> Pair;
const int maxn = 500+10;
const int MAX_V= 500+10;
int a[maxn],b[maxn],c[maxn],d[maxn];
struct Edge{
int from,to,cap,cost;
Edge(int f,int t,int c,int co):from(f),to(t),cap(c),cost(co){}
};
std::vector E;
std::vector<int> G[MAX_V];
void add_edge(int u,int v,int cap,int cost){
E.push_back(Edge(u,v,cap,cost));G[u].push_back(E.size()-1);
E.push_back(Edge(v,u,0,-cost)) ;G[v].push_back(E.size()-1);
}
struct MCMF{
int dist[MAX_V];
int pre_E[MAX_V];//最短路径弧
bool inq[MAX_V];//spfa判断
//未判断负圈
void spfa(int s){
memset(dist,INF,sizeof(dist));
memset(inq,false,sizeof(inq));
queue<int> Q;
Q.push(s);
dist[s] = 0;
inq[s] = true;
pre_E[s] = -1;
while(!Q.empty())
{
int u = Q.front();Q.pop();
inq[u] = false;
for(int i=0 ; iif(e.cap>0&&dist[e.to]>dist[u]+e.cost){
dist[e.to] = dist[u]+e.cost;
pre_E[e.to] = G[u][i];
if(!inq[e.to]){Q.push(e.to);inq[e.to] = true;}
}
}
}
}
int min_cost_flow(int s,int t,int f){
int res = 0;
while (f>0) {
spfa(s);
if(dist[t]>0)break;//不能增广
//沿着最短路增广
int d = f;
for(int i = pre_E[t] ; i!=-1 ;i = pre_E[E[i].from])d = min(d,E[i].cap);
f-=d;
res+=d*dist[t];
for(int i = pre_E[t] ; i!=-1 ;i = pre_E[E[i].from]){
E[i].cap-=d;
E[i^1].cap+=d;
}
}
return res;
}
};
MCMF flow;
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n,m;
while (cin>>n >> m) {
E.clear();
for(int i=0 ; i<=n+1 ; ++i)G[i].clear();
for(int i=1 ; i<=n ; ++i)cin>>a[i]>>b[i]>>c[i]>>d[i];
for(int i=0 ; iint u,v,x;cin>>u>>v >> x;
if(u == v)continue;
add_edge(u,v,INF,x);
add_edge(v,u,INF,x);
}
int s = 0,t =n+1;
for(int i=1 ; i<=n ; ++i){
add_edge(s,i,b[i],a[i]);
add_edge(i,t,d[i],-c[i]);
}
int ans = flow.min_cost_flow(s,t,INF);
std::cout << max(0,-ans) << '\n';
}
return 0;
}