后缀数组(Suffix Arrary)

• First things first

  这玩意似乎我17年搞过，但是现在毫无记忆qwq

  用处是对后缀排序，和求LCS

• 正文

  倍增法很好理解，运用基数排序，每次排序一倍长度的前缀

  qwq

  这点东西背板子比较好

  详细解释留坑

(update on 7.18.2019)
New Code!

/*
@Date    : 2019-07-18 16:46:50
@Author  : Adscn (adscn@qq.com)
@Link    : https://www.cnblogs.com/LLCSBlog
*/
#include<bits/stdc++.h>
using namespace std;
#define IL inline
#define RG register
#define gi getint()
#define gc getchar()
#define File(a) freopen(a".in","r",stdin);freopen(a".out","w",stdout)
IL int getint()
{
	RG int xi=0;
	RG char ch=gc;
	bool f=0;
	while(ch<'0'|ch>'9')ch=='-'?f=1:f,ch=gc;
	while(ch>='0'&ch<='9')xi=(xi<<1)+(xi<<3)+ch-48,ch=gc;
	return f?-xi:xi;
}
template<typename T>
IL void pi(T k,char ch=0)
{
	if(k<0)k=-k,putchar('-');
	if(k>=10)pi(k/10,0);
	putchar(k%10+'0');
	if(ch)putchar(ch);
}
const int N=1e7+7;
namespace SuffixArray{
	static char s[N];
	static int sa[N],rkx[N],rky[N],n,m,*key1,*key2,rank[N];
	int cnt[300];
	void In(){scanf("%s",s+1);n=strlen(s+1);}
	inline void Qsort()
	{
		memset(cnt,0,sizeof(int)*m+sizeof(int)*7);
		for(int i=1;i<=n;++i)++cnt[key1[i]];
		for(int i=1;i<=m;++i)cnt[i]+=cnt[i-1];
		for(int i=n;i;--i)sa[cnt[key1[key2[i]]]--]=key2[i];
	}
	void Get()
	{
		m=150,key1=rkx,key2=rky;
		for(int i=1;i<=n;++i)
			key1[i]=s[i],key2[i]=i;
		Qsort();
		for(int k=1,p=0;p<n;k<<=1)
		{
			p=0;	
			for(int i=n-k+1;i<=n;++i)key2[++p]=i;//this key2 mean the second key 's address not rank
			for(int i=1;i<=n;++i)if(sa[i]>k)key2[++p]=sa[i]-k;
			Qsort();
			swap(key1,key2);
			p=key1[sa[1]]=1;
			for(int i=2;i<=n;++i)
				key1[sa[i]]=(
					key2[sa[i-1]]==key2[sa[i]]&&
					key2[sa[i-1]+k]==key2[sa[i]+k])?p:++p;
			m=p;
		}
		for(int i=1;i<=n;i++)rank[sa[i]]=i;
	}
	void getheight()
	{
		int k=0;
		for(int i=1;i<=n;i++)
		{
			if(k)--k;
			int p=sa[rank[i]-1];
			while(s[i+k]==s[p+k])++k;
			height[rank[i]]=k;
		}
	}
	void print()
	{
		for(int i=1;i<=n;++i)pi(sa[i],' ');
	}
}
int main(void)
{
	SuffixArray::In();
	SuffixArray::Get();
	SuffixArray::print();
	return 0;
}