POJ1509 Glass Beads 【后缀自动机】

题目分析：

模板练手。看最长能走多远。

代码:

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<string>
using namespace std;

const int maxn = 50500;

int son[maxn][30],fa[maxn],maxlen[maxn],root,num;

string str;

int addnew(int dt){maxlen[++num] = dt;return num;}
int ins(char x,int p){
    int np = addnew(maxlen[p]+1);
    while(p && !son[p][x-'a']) son[p][x-'a'] = np,p = fa[p];
    if(!p){fa[np] = root; return np;}
    else{
    int q = son[p][x-'a'];
    if(maxlen[q]==maxlen[p]+1){fa[np]=q;return np;}
    else{
        int nq = addnew(maxlen[p]+1);
        for(int i=0;i<26;i++) son[nq][i] = son[q][i];
        fa[nq] = fa[q]; fa[q] = fa[np] = nq;
        while(p && son[p][x-'a'] == q) son[p][x-'a'] = nq,p = fa[p];
        return np;
    }
    }
}

void dfs(int now,int cnt){
    int flag = 0;
    for(int i=0;i<26;i++){
    if(!son[now][i]) continue;
    dfs(son[now][i],cnt+1); flag = 1;
    break;
    }
    if(!flag){cout<<str.length()-cnt+1<<endl;}
}

void init(){
    for(int i=1;i<=num;i++) memset(son[i],0,sizeof(son[i]));
    for(int i=1;i<=num;i++) fa[i] = maxlen[i] = 0;
    root = 0; num = 0;
}

void work(){
    int lst = addnew(0);root = lst;
    for(int i=0;i<str.length();i++)
    lst = ins(str[i],lst);
    dfs(root,0);
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int Tmp; cin >> Tmp;
    while(Tmp--){
    init();
    cin >> str;
    str+=str;
    work();
    }
    return 0;
}