hdu 3605 Escape 状态压缩+最大流
2015-11-01 18:46
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[code]#include<stdio.h> #include<string.h> #include<algorithm> #include<iostream> using namespace std; const int MAXN=100010;//点数的最大值 const int MAXM=400010;//边数的最大值 const int INF=0x3f3f3f3f; struct Node { int from,to,next; int cap; }edge[MAXM]; int tol; int head[MAXN]; int dep[MAXN]; int gap[MAXN];//gap[x]=y :说明残留网络中dep[i]==x的个数为y int n;//n是总的点的个数,包括源点和汇点 void init() { tol=0; memset(head,-1,sizeof(head)); } void addedge(int u,int v,int w) { edge[tol].from=u; edge[tol].to=v; edge[tol].cap=w; edge[tol].next=head[u]; head[u]=tol++; edge[tol].from=v; edge[tol].to=u; edge[tol].cap=0; edge[tol].next=head[v]; head[v]=tol++; } void BFS(int start,int end) { memset(dep,-1,sizeof(dep)); memset(gap,0,sizeof(gap)); gap[0]=1; int que[MAXN]; int front,rear; front=rear=0; dep[end]=0; que[rear++]=end; while(front!=rear) { int u=que[front++]; if(front==MAXN)front=0; for(int i=head[u];i!=-1;i=edge[i].next) { int v=edge[i].to; if(dep[v]!=-1)continue; que[rear++]=v; if(rear==MAXN)rear=0; dep[v]=dep[u]+1; ++gap[dep[v]]; } } } int SAP(int start,int end) { int res=0; BFS(start,end); int cur[MAXN]; int S[MAXN]; int top=0; memcpy(cur,head,sizeof(head)); int u=start; int i; while(dep[start]<n) { if(u==end) { int temp=INF; int inser; for(i=0;i<top;i++) if(temp>edge[S[i]].cap) { temp=edge[S[i]].cap; inser=i; } for(i=0;i<top;i++) { edge[S[i]].cap-=temp; edge[S[i]^1].cap+=temp; } res+=temp; top=inser; u=edge[S[top]].from; } if(u!=end&&gap[dep[u]-1]==0)//出现断层,无增广路 break; for(i=cur[u];i!=-1;i=edge[i].next) if(edge[i].cap!=0&&dep[u]==dep[edge[i].to]+1) break; if(i!=-1) { cur[u]=i; S[top++]=i; u=edge[i].to; } else { int min=n; for(i=head[u];i!=-1;i=edge[i].next) { if(edge[i].cap==0)continue; if(min>dep[edge[i].to]) { min=dep[edge[i].to]; cur[u]=i; } } --gap[dep[u]]; dep[u]=min+1; ++gap[dep[u]]; if(u!=start)u=edge[S[--top]].from; } } return res; } int main() { int i,j,c,N,m,s,t,a[2048],b,cnt; while(~scanf("%d%d",&N,&m)) { init(); s=0; n=1100+m+2; memset(a,0,sizeof(a)); for(i=1; i<=N; i++) { t=0; for(j=1; j<=m; j++) { scanf("%d",&c); t*=2; if(c) t+=1; } a[t]++; } for(i=0;i<=1024;i++) { if(a[i]==0) continue; addedge(s,i,a[i]); c=i; cnt=m; while(c) { b=c%2; c/=2; if(b) { addedge(i,cnt+1100,100000+5); //printf("%d %d %d\n",i,cnt+1100,a[i]); } cnt--; } } for(i=1; i<=m; i++) { scanf("%d",&c); addedge(i+1100,n,c); //printf("%d %d\n",i+1100,c); } if(SAP(s,n)==N) printf("YES\n"); else printf("NO\n"); } return 0; }
[code]#include<stdio.h> #include<string.h> #include<algorithm> #include<iostream> #include<vector> #include<queue> using namespace std; const int N=4048; const int inf=1<<24; struct Edge { int from,to,cap,flow; }; vector<Edge>edges; vector<int>G ; int n,m,s,t; int vis ; int d ; int cur ; void AddEdge(int from,int to,int cap) { Edge tp; tp.from=from,tp.to=to,tp.cap=cap,tp.flow=0; edges.push_back(tp); tp.from=to,tp.to=from,tp.cap=0,tp.flow=0; edges.push_back(tp); int g_size=edges.size(); G[from].push_back(g_size-2); G[to].push_back(g_size-1); } bool BFS() { memset(vis,0,sizeof(vis)); queue<int>Q; Q.push(s); d[s]=0; vis[s]=1; while(!Q.empty()) { int x=Q.front(); Q.pop(); for(int i=0; i<G[x].size(); i++) { Edge &e=edges[G[x][i]]; if(!vis[e.to]&&e.cap>e.flow) { vis[e.to]=1; d[e.to]=d[x]+1; Q.push(e.to); } } } return vis[t]; } int DFS(int x,int a) { if(x==t||a==0) return a; int flow=0,f; for(int &i=cur[x]; i<G[x].size(); i++) { Edge &e=edges[G[x][i]]; if(d[x]+1==d[e.to]&&(f=DFS(e.to,min(a,e.cap-e.flow)))>0) { e.flow+=f; edges[G[x][i]^1].flow-=f; flow+=f; a-=f; if(a==0) break; } } if(!flow) d[x] = -1; return flow; } int Maxflow(int st,int ed) { int flow=0; while(BFS()) { memset(cur,0,sizeof(cur)); flow+=DFS(st,inf); //printf("%d\n",flow); } return flow; } int main() { int _,i,j,tn,cnt; int c,a[2048],b; while(~scanf("%d%d",&tn,&m)) { edges.clear(); for(i=0; i<N; i++) G[i].clear(); s=1100+m+2; n=1100+m+1; memset(a,0,sizeof(a)); for(i=1; i<=tn; i++) { t=0; for(j=1; j<=m; j++) { scanf("%d",&c); t*=2; if(c) t+=1; } a[t]++; } for(i=0;i<=1024;i++) { if(a[i]==0) continue; AddEdge(s,i,a[i]); c=i; cnt=m; while(c) { b=c%2; c/=2; if(b) { AddEdge(i,cnt+1100,100000+5); //printf("%d %d %d\n",i,cnt+1100,a[i]); } cnt--; } } for(i=1; i<=m; i++) { scanf("%d",&c); AddEdge(i+1100,n,c); printf("%d %d\n",i+1100,c); } int ans=Maxflow(s,n); //printf("%d\n",ans); if(ans==tn) printf("YES\n"); else printf("NO\n"); } return 0; }
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