loj 102 最小费用流
补一发费用流的代码
%%%棒神
1 #include<iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<cstdlib> 5 #include<cmath> 6 #include<algorithm> 7 #include<queue> 8 #include<vector> 9 #include<map> 10 #define ll long long 11 #define inf 2139062143 12 #define MAXN 420 13 using namespace std; 14 inline int read() 15 { 16 int x=0,f=1;char ch=getchar(); 17 while(!isdigit(ch)) {if(ch=='-') f=-1;ch=getchar();} 18 while(isdigit(ch)) x=x*10+ch-'0',ch=getchar(); 19 return x*f; 20 } 21 int n,m,ans; 22 struct ZKW 23 { 24 int fst[MAXN],to[MAXN*80],nxt[MAXN*80],val[MAXN*80],cos[MAXN*80],cnt; 25 int dis[MAXN],s,t,vis[MAXN]; 26 ZKW() {ans=0,cnt=2;}//memset(fst,0xff,sizeof(fst));} 27 void add(int u,int v,int w,int c) {nxt[cnt]=fst[u],fst[u]=cnt,to[cnt]=v,val[cnt]=w,cos[cnt++]=c;} 28 int spfa() 29 { 30 memset(dis,127,sizeof(dis)); 31 queue<int> q; 32 dis[t]=0,vis[t]=1; 33 q.push(t); 34 while(!q.empty()) 35 { 36 int x=q.front();q.pop();vis[x]=0; 37 for(int i=fst[x];i;i=nxt[i]) 38 if(val[i^1]&&dis[to[i]]>dis[x]-cos[i]) 39 { 40 dis[to[i]]=dis[x]-cos[i]; 41 if(!vis[to[i]]) {q.push(to[i]);vis[to[i]]=1;} 42 } 43 } 44 memset(vis,0,sizeof(vis)); 45 return dis[s]!=inf; 46 } 47 int dfs(int x,int a) 48 { 49 if(x==t||!a) {ans+=dis[s]*a;return a;} 50 if(vis[x])return 0; 51 vis[x]=1; 52 int res=0,f; 53 for(int i=fst[x];i&&a;i=nxt[i]) 54 if(dis[to[i]]==dis[x]-cos[i]&&(f=dfs(to[i],min(a,val[i])))) 55 res+=f,val[i]-=f,val[i^1]+=f,a-=f; 56 vis[x]=0; 57 return res; 58 } 59 int solve() 60 { 61 int f=0; 62 while(spfa()) f+=dfs(s,2147483647); 63 return f; 64 } 65 }Z; 66 int main() 67 { 68 n=read(),m=read();int a,b,c,d; 69 while(m--) 70 { 71 a=read(),b=read(),c=read(),d=read(); 72 Z.add(a,b,c,d); 73 Z.add(b,a,0,-d); 74 } 75 Z.s=1,Z.t=n; 76 printf("%d ",Z.solve()); 77 printf("%d",ans); 78 }
