BZOJ4199 [Noi2015]品酒大會__BZOJ

建一個尾碼樹，dfs一遍維護子樹裡有多少個尾碼，子數內最大次大最小次小，用siz[x]*(siz[x]-1)/2可以更新mx[fa[x]]+1~mx[x]這段的選法，用max(mx1[x]*mx2[x],mn1[x]*mn2[x])可以更新mx[fa[x]]+1~mx[x]這段的最大值，拿個線段樹維護一下，然後爬一遍線段樹就可以了

感覺自從學會了尾碼數組半個月之後學會了尾碼自動機就再也沒打過尾碼數組-_-

#include<iostream>#include<cstdlib>#include<cstdio>#include<cstring>#include<cmath>#include<ctime>#include<algorithm>#include<iomanip>#include<vector>#include<stack>#include<queue>#include<map>#include<set>#include<bitset>using namespace std;#define MAXN 600010#define MAXM 1010#define ll long long#define INF 2000000000#define MOD 1000000007#define eps 1e-8struct vec{int to;int fro;};vec mp[MAXN];int tai[MAXN],cnt;int fa[MAXN],son[MAXN][26],mx[MAXN];int lst,rt,tot;int n;char s[MAXN];int P[MAXN];int a[MAXN];ll v1[MAXN<<1],v2[MAXN<<1];int siz[MAXN],MX[MAXN][5],MN[MAXN][5];inline void be(int x,int y){mp[++cnt].to=y;mp[cnt].fro=tai[x];tai[x]=cnt;}void ins(int x){int np=++tot,p=lst;mx[np]=mx[p]+1;while(p&&!son[p][x]){son[p][x]=np;p=fa[p];}if(!p){fa[np]=rt;}else{int q=son[p][x];if(mx[q]==mx[p]+1){fa[np]=q;}else{int nq=++tot;mx[nq]=mx[p]+1;memcpy(son[nq],son[q],sizeof(son[q]));fa[nq]=fa[q];fa[np]=fa[q]=nq;while(p&&son[p][x]==q){son[p][x]=nq;p=fa[p];}}}lst=np;}void add(int x,int y,int z,int l,int r,ll av){if(y==l&&z==r){v1[x]+=av;return ;}int mid=y+z>>1;if(r<=mid){add(x<<1,y,mid,l,r,av);}else if(l>mid){add(x<<1|1,mid+1,z,l,r,av);}else{add(x<<1,y,mid,l,mid,av);add(x<<1|1,mid+1,z,mid+1,r,av);}}void change(int x,int y,int z,int l,int r,ll cv){if(y==l&&z==r){v2[x]=max(v2[x],cv);return ;}int mid=y+z>>1;if(r<=mid){change(x<<1,y,mid,l,r,cv);}else if(l>mid){change(x<<1|1,mid+1,z,l,r,cv);}else{change(x<<1,y,mid,l,mid,cv);change(x<<1|1,mid+1,z,mid+1,r,cv);}}void dfs(int x){int i,y;ll t=0;for(i=tai[x];i;i=mp[i].fro){y=mp[i].to;dfs(y);siz[x]+=siz[y];MX[x][0]=MX[y][3];MX[x][1]=MX[y][2];MN[x][2]=MN[y][0];MN[x][3]=MN[y][1];sort(MX[x],MX[x]+4);sort(MN[x],MN[x]+4);}t=(ll)siz[x]*(siz[x]-1)/2;int l=mx[fa[x]]+1,r=min(mx[x],n-1);if(siz[x]>=2){add(1,0,n-1,l,r,t);change(1,0,n-1,l,r,max((ll)MX[x][3]*MX[x][2],(ll)MN[x][0]*MN[x][1]));}}void walk(int x,int y,int z,ll ans1,ll ans2){ans1+=v1[x];ans2=max(ans2,v2[x]);if(y==z){if(ans1){printf("%lld %lld\n",ans1,ans2);}else{printf("0 0\n");}return ;}int mid=y+z>>1;walk(x<<1,y,mid,ans1,ans2);walk(x<<1|1,mid+1,z,ans1,ans2);}int main(){lst=rt=tot=1;int i;scanf("%d",&n);scanf("%s",s+1);int p=rt;for(i=n;i;i--){ins(s[i]-'a');siz[P[i]=p=son[p][s[i]-'a']]++;}for(i=1;i<=tot;i++){MX[i][0]=MX[i][1]=MX[i][2]=MX[i][3]=-INF;MN[i][0]=MN[i][1]=MN[i][2]=MN[i][3]=INF;}for(i=1;i<=n;i++){scanf("%d",&MX[P[i]][3]);MN[P[i]][0]=MX[P[i]][3];}for(i=2;i<=tot;i++){be(fa[i],i);}mx[0]=-1;for(i=1;i<=n*4;i++){v2[i]=-((ll)INF*INF);}dfs(1);walk(1,0,n-1,0,-((ll)INF*INF));return 0;}/**/