zoukankan      html  css  js  c++  java
  • Substrings(SPOJ8222) (sam(后缀自动机))

    You are given a string (S) which consists of 250000 lowercase latin letters at most. We define (F(x)) as the maximal number of times that some string with length (x) appears in (S). For example for string 'ababa' (F(3)) will be 2 because there is a string 'aba' that occurs twice. Your task is to output (F(i)) for every (i) so that (1<=i<=|S|).

    Input

    String (S) consists of at most 250000 lowercase latin letters.

    Output

    Output (|S|) lines. On the (i-th) line output (F(i)).

    Example

    Input:

    ababa
    

    Output:

    3
    2
    2
    1
    1
    

    题意:

    给定一个字符串(S),令(F(x))表示(S)中所有长度为(x)的子串出现最多的次数,

    题解:

    把串塞进一个后缀自动机,在(parent)树上反向拓扑,求出每个长度时的最大值。

    #include<bits/stdc++.h>
    using namespace std;
    const int N=2000010;
    char s[N];
    int a[N],c[N],ans[N];
    struct SAM{
    	int last,cnt;
    	int size[N],ch[N][26],fa[N<<1],l[N<<1];
    	void ins(int c){
    		int p=last,np=++cnt;last=np;l[np]=l[p]+1;
    		for(;p&&!ch[p][c];p=fa[p])ch[p][c]=np;
    		if(!p)fa[np]=1;
    		else{
    			int q=ch[p][c];
    			if(l[p]+1==l[q])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][c]==q;p=fa[p])ch[p][c]=nq;
    			}
    		}
    		size[np]=1;
    	}
    	void build(char s[]){
    		int len=strlen(s+1);
    		last=cnt=1;
    		for(int i=1;i<=len;++i)ins(s[i]-'a');
    	}
    	void calc(int len){
    		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;
    		for(int i=cnt;i;--i){
    			int p=a[i];
    			size[fa[p]]+=size[p];
    			ans[l[p]]=max(ans[l[p]],size[p]);
    		}
    		for(int i=1;i<=len;++i){
    			printf("%d
    ",ans[i]);
    		}
    	}
    }sam;
    int main(){
    	cin>>s+1;
    	sam.build(s);
    	sam.calc(strlen(s+1));
    }
    
  • 相关阅读:
    R学习笔记3 数据处理
    R学习笔记2 因子
    R学习笔记1 介绍R的使用
    正则表达式之邮箱、手机号码、电话号码,url地址
    vue之axios运用
    angularJS导出数据到Excel
    vue2全选反选
    css设置垂直居中
    js实现鼠标选中文本改变选中区域颜色以及给选中区域加上html标签
    安装了Vetur之后的配置
  • 原文地址:https://www.cnblogs.com/zhenglier/p/10097776.html
Copyright © 2011-2022 走看看