hdu Party at Hali-Bula 树形最大独立集 刷表递推解

//使用"刷表"Dp即刻递推求解

//做的时候忽视了以个bug,,就是忘记盘入度是0的时候再加入队列了

#include <iostream>#include <queue>#include <stack>#include <string>#include <map>#include <vector>#include <cstring>#include <cstdio>#include <cmath>#include <algorithm>using namespace std;const int MAX=205,INF=1<<30;int n,l;map<string,int> mymap;map<string,int>::iterator it;struct State{ int s,gs; int val;};int root;int fa[MAX];int degree[MAX];bool inqueue[MAX];int Queue[MAX],front,rear;State d[MAX];bool G[MAX][MAX];bool unique(int boss){ bool flag; int s=d[boss].s,gs=d[boss].gs; if(s==gs){ return 0; } else if(s>gs){ flag=1; for(int i=1;i<l;i++){ if(G[boss][i]&&!unique(i)){ flag=0; } } } else{ flag=1; for(int i=1;i<l;i++){ if(G[boss][i]){ for(int j=1;j<l;j++){ if(G[i][j]&&!unique(j)){ flag=0; } } } } } return flag;}int main(){#ifndef ONLINE_JUDGE freopen("i.txt", "r", stdin);#endif string name,e,b; int u,v,gv; while(cin>>n,n){ l=1; mymap.clear(); memset(degree,0,sizeof(degree)); memset(inqueue,0,sizeof(inqueue)); memset(G,0,sizeof(G)); cin>>name; mymap[name]=root=l++; for(int i=0;i<n-1;i++){ cin>>e>>b; it=mymap.find(e); if(it!=mymap.end()) u=it->second; else mymap[e]=u=l++; it=mymap.find(b); if(it!=mymap.end()) v=it->second; else mymap[b]=v=l++; ++degree[v]; fa[u]=v; G[v][u]=1; } front=0; rear=0; for(int i=1;i<l;i++){ if(!degree[i]){ inqueue[i]=1; Queue[rear++]=i; } } for(int i=0;i<l;i++){ d[i].s=0; d[i].gs=1; } while(front<rear){ u=Queue[front++]; d[u].val=max(d[u].s,d[u].gs); v=fa[u]; gv=fa[v]; d[v].s+=d[u].val; d[gv].gs+=d[u].val; --degree[v];// 错误的方法:没有判断入度为0就加入队列,导致状态的无序// if(!inqueue[v]){// inqueue[v]=1;// Queue[rear++]=v;// } if(!inqueue[v]&°ree[v]<=0){ inqueue[v]=1; Queue[rear++]=v; } } cout<<d[root].val<<" "; if(unique(root)) cout<<"Yes"<<endl; else cout<<"No"<<endl; } return 0;}