• ACM-ICPC World Finals 2019 G.First of Her Name


    题意:给一颗字典树,m次查询,每次给出一个字符串,问你该字符串是字典树上多少串的后缀
    题解:字典树求广义sam,每次把查询串在sam上跑一遍,最后到达的点的sz就是答案,中途没法走了,就是没有出现过

    //#pragma GCC optimize(2)
    //#pragma GCC optimize(3)
    //#pragma GCC optimize(4)
    //#pragma GCC optimize("unroll-loops")
    //#pragma comment(linker, "/stack:200000000")
    //#pragma GCC optimize("Ofast,no-stack-protector")
    //#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
    #include<bits/stdc++.h>
    #define fi first
    #define se second
    #define db double
    #define mp make_pair
    #define pb push_back
    #define pi acos(-1.0)
    #define ll long long
    #define vi vector<int>
    #define mod 1000000007
    #define ld long double
    //#define C 0.5772156649
    //#define ls l,m,rt<<1
    //#define rs m+1,r,rt<<1|1
    #define pll pair<ll,ll>
    #define pil pair<int,ll>
    #define pli pair<ll,int>
    #define pii pair<int,int>
    #define ull unsigned long long
    //#define base 1000000000000000000
    #define fin freopen("a.txt","r",stdin)
    #define fout freopen("a.txt","w",stdout)
    #define fio ios::sync_with_stdio(false);cin.tie(0)
    inline ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
    inline void sub(ll &a,ll b){a-=b;if(a<0)a+=mod;}
    inline void add(ll &a,ll b){a+=b;if(a>=mod)a-=mod;}
    template<typename T>inline T const& MAX(T const &a,T const &b){return a>b?a:b;}
    template<typename T>inline T const& MIN(T const &a,T const &b){return a<b?a:b;}
    inline ll qp(ll a,ll b){ll ans=1;while(b){if(b&1)ans=ans*a%mod;a=a*a%mod,b>>=1;}return ans;}
    inline ll qp(ll a,ll b,ll c){ll ans=1;while(b){if(b&1)ans=ans*a%c;a=a*a%c,b>>=1;}return ans;}
    
    using namespace std;
    
    const ull ba=233;
    const db eps=1e-5;
    const ll INF=0x3f3f3f3f3f3f3f3f;
    const int N=1000000+10,maxn=1000000+10,inf=0x3f3f3f3f;
    
    char s[N];
    struct SAM{
        int last,cnt;
        int ch[N<<1][26],fa[N<<1],l[N<<1],sz[N<<1];
        int c[N<<1],a[N<<1];
        int ins(int y,int x)
        {
            last=y;
            int p=last,np=++cnt;last=np;l[np]=l[p]+1;
            for(;p&&!ch[p][x];p=fa[p])ch[p][x]=np;
            if(!p)fa[np]=1;
            else
            {
                int q=ch[p][x];
                if(l[q]==l[p]+1)fa[np]=q;
                else
                {
                    int nq=++cnt;l[nq]=l[p]+1;
                    memcpy(ch[nq],ch[q],sizeof ch[q]);
                    fa[nq]=fa[q];fa[q]=fa[np]=nq;
                    for(;ch[p][x]==q;p=fa[p])ch[p][x]=nq;
                }
            }
            sz[np]=1;
            return last;
        }
        void build()
        {
            cnt=last=1;
        }
        void topo()
        {
            for(int i=1;i<=cnt;i++)c[l[i]]++;
            for(int i=1;i<=cnt;i++)c[i]+=c[i-1];
            for(int i=1;i<=cnt;i++)a[c[l[i]]--]=i;
        }
        void gao()
        {
            topo();
            for(int i=cnt;i;i--)sz[fa[a[i]]]+=sz[a[i]];
        }
        void cal()
        {
            int len=strlen(s+1),now=1;
            for(int i=len;i>=1;i--)
            {
                if(ch[now][s[i]-'A'])now=ch[now][s[i]-'A'];
                else
                {
                    puts("0");
                    return ;
                }
            }
            printf("%d
    ",sz[now]);
        }
    }sam;
    int a[N],id[N];
    struct Tire{
        vector<int>v[N];
        void bfs()
        {
            queue<int>q;q.push(0);id[0]=1;
            while(!q.empty())
            {
                int u=q.front();q.pop();
                for(int i=0;i<v[u].size();i++)if(v[u][i])
                {
                    id[v[u][i]]=sam.ins(id[u],a[v[u][i]]);
                    q.push(v[u][i]);
                }
            }
        }
    }t;
    int main()
    {
        int n,m;scanf("%d%d",&n,&m);
        for(int i=1;i<=n;i++)
        {
            int x;scanf("%s%d",s,&x);
            t.v[x].pb(i);a[i]=s[0]-'A';
        }
        sam.build();
        t.bfs();
        sam.gao();
        while(m--)
        {
            scanf("%s",s+1);
            sam.cal();
        }
        return 0;
    }
    /********************
    
    ********************/
    
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  • 原文地址:https://www.cnblogs.com/acjiumeng/p/10661634.html
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