ZSOI2012 捡金子 字典树+树形DP

我们显然可以用字典树来维护这个东西，然后上面跑树形DP

唯一比较虚的是动态的字典树就有三个点超时= =静态的就跑的超快了

代码中含有静态的动态的代码

#include<iostream>#include<cstdio>#include<cmath>#include<cstring>#include<cstdlib>#include<algorithm>#include<ctime>#define LL long long#define fo(i,a,b) for(int i=a;i<=b;i++)#define fd(i,a,b) for(int i=a;i>=b;i--)#define efo(i,x) for(int i=last[x];i!=0;i=e[i].next)using namespace std;inline LL read(){LL d=0,f=1;char s=getchar();while(s<'0'||s>'9'){if(s=='-')f=-1;s=getchar();}while(s>='0'&&s<='9'){d=d*10+s-'0';s=getchar();}return d*f;}#define N 50005#define M 12#define K 27#define L 55#define sonmax 26int n=0,m,nm;int fa[N];int f[N][M];struct edge{int y,next;}e[N*2];int last[N],ne=0;struct st{int len;char s[L];}a[N];struct sor{int a,b;}b[N];bool strcom(sor a,sor b){return a.b<b.b;}void add(int x,int y){//cout<<x<<' '<<y<<endl;e[++ne].y=y;e[ne].next=last[x];last[x]=ne;}//the dynamic trie is too slow/*typedef struct node{int num;int xu;bool terminal;struct node * next[sonmax];}*trie,node;trie root;void init_trie(trie &p){p=(trie)malloc(sizeof(node));for(int i=0;i<26;i++)p->next[i]=0;p->terminal=0;p->num=0;}void insert(trie p,char str[]){int i=0,cnt=0;while(str[i]!='\0'){if(!p->next[str[i]-'A']){trie q;init_trie(q);p->next[str[i]-'A']=q;}p=p->next[str[i]-'A'];p->num++;if(p->terminal)cnt=p->xu;i++;}if(p->terminal)cout<<"STOP!!!!!!!!!!!!!!!!!!!!!!!!!"<<endl;p->terminal=1;p->xu=++n;add(cnt,n);fa[n]=cnt;}*///set the static trietypedef struct node{int xu;bool terminal;int next[26];void clear(){terminal=0;xu=0;memset(next,0,sizeof(next));}}Trietree;Trietree trie[1200000];int xu=0;void insert(char str[]){int i=0,cnt=0,k=0;while(str[i]!='\0'){if(trie[k].next[str[i]-'A']==0){xu++;trie[xu].clear();trie[k].next[str[i]-'A']=xu;}k=trie[k].next[str[i]-'A'];if(trie[k].terminal==1)cnt=trie[k].xu;i++;}trie[k].terminal=1;trie[k].xu=++n;add(cnt,n);fa[n]=cnt;}void dfs(int x){fo(i,0,nm)f[x][i]=0;efo(i,x){dfs(e[i].y);fd(j,nm,1){fo(k,1,j)f[x][j]=max(f[x][j],f[x][j-k]+f[e[i].y][k]);}}if(x!=0)fo(i,1,nm)f[x][i]++;f[x][0]=0;//cout<<"DP:"<<x<<' '<<f[x][1]<<' '<<f[x][2]<<endl;}int main(){double tt=clock();freopen("gold.in","r",stdin);freopen("gold.out","w",stdout);//init_trie(root);trie[0].clear();m=read(),read(),read(),nm=read();fo(i,1,m){scanf("%s",a[i].s);a[i].len=strlen(a[i].s);b[i].a=i;b[i].b=a[i].len;//insert(root,s);}sort(b+1,b+m+1,strcom);fo(i,1,m){insert(a[b[i].a].s);//insert(root,a[b[i].a].s);//cout<<i<<' '<<a[b[i].a].s<<endl;}dfs(0);int ans=0;fo(i,1,nm)ans=max(ans,f[0][i]);cout<<ans<<endl;printf("%lf\n",clock()-tt);return 0;}