【CF 547E】 Mike and Friends

题目

显然SAM版题，写它的原因就是我太颓了；之后学习了一下正规的广义SAM写法，争取以后不再写lst=1

代码

#include<bits/stdc++.h>
#define re register
const int maxn=4e5+5;
const int M=maxn*30;
struct E{int v,nxt;}e[maxn];char S[maxn>>1];
int l[M],r[M],d[M],tot,q;
int lst,cnt,n,L,num,dep[maxn],lg[maxn],head[maxn],f[20][maxn];
int fa[maxn],son[maxn][26],len[maxn],rt[maxn],pos[maxn>>1],ln[maxn>>1];
inline void add(int x,int y) {
    e[++num].v=y;e[num].nxt=head[x];head[x]=num;
}
int chg(int nw,int x,int y,int pos) {
    if(!nw)nw=++tot;d[nw]++;if(x==y)return nw;int mid=x+y>>1;
    pos<=mid?l[nw]=chg(l[nw],x,mid,pos):r[nw]=chg(r[nw],mid+1,y,pos);return nw;
}
int merge(int a,int b,int x,int y) {
    if(!a||!b)return a|b;int nw=++tot;
    if(x==y) {d[nw]=d[a]+d[b];return nw;}int mid=x+y>>1;
    l[nw]=merge(l[a],l[b],x,mid);r[nw]=merge(r[a],r[b],mid+1,y);
    d[nw]=d[l[nw]]+d[r[nw]];return nw;
}
int qry(int nw,int x,int y,int lx,int ry) {
    if(!nw)return 0;if(lx<=x&&ry>=y)return d[nw];int mid=x+y>>1;
    return (lx<=mid?qry(l[nw],x,mid,lx,ry):0)+(ry>mid?qry(r[nw],mid+1,y,lx,ry):0);
}
void dfs(int x) {
    for(re int i=1;i<=lg[dep[x]];++i)f[i][x]=f[i-1][f[i-1][x]];
    for(re int i=head[x];i;i=e[i].nxt)
        dep[e[i].v]=dep[x]+1,dfs(e[i].v),rt[x]=merge(rt[x],rt[e[i].v],1,n);
}
inline void ins(int c) {
    if(son[lst][c]) {
        int f=lst,x=son[f][c];
        if(len[f]+1==len[x]) {lst=x;return;}
        int y=++cnt;len[y]=len[f]+1;fa[y]=fa[x];fa[x]=y;
        for(re int i=0;i<26;i++)son[y][i]=son[x][i];
        while(f&&son[f][c]==x)son[f][c]=y,f=fa[f];
        lst=y;return;
    }
    int p=++cnt,f=lst;lst=p;len[p]=len[f]+1;
    while(f&&!son[f][c]) son[f][c]=p,f=fa[f];
    if(!f){fa[p]=1;return;}
    int x=son[f][c];
    if(len[f]+1==len[x]){fa[p]=x;return;}
    int y=++cnt;len[y]=len[f]+1,fa[y]=fa[x],fa[x]=fa[p]=y;
    for(re int i=0;i<26;i++)son[y][i]=son[x][i];
    while(f&&son[f][c]==x)son[f][c]=y,f=fa[f];
}
int main() {
    scanf("%d%d",&n,&q);cnt=1;
    for(re int i=1;i<=n;i++) {
        scanf("%s",S+1);int L=strlen(S+1);lst=1;ln[i]=L;
        for(re int j=1;j<=L;++j) ins(S[j]-'a'),rt[lst]=chg(rt[lst],1,n,i);
        pos[i]=lst;
    }
    for(re int i=2;i<=cnt;i++)add(fa[i],i),f[0][i]=fa[i];
    for(re int i=2;i<=cnt;i++)lg[i]=lg[i>>1]+1;
    dep[1]=1,dfs(1);int x,y,k,lim;
    while(q--) {
        scanf("%d%d%d",&x,&y,&k);lim=ln[k],k=pos[k];
        for(re int j=lg[dep[k]];j>=0;--j)k=len[f[j][k]]>=lim?f[j][k]:k;
        printf("%d\n",qry(rt[k],1,n,x,y));
    }
    return 0;
}

原文地址：https://www.cnblogs.com/asuldb/p/12219350.html