理解神马的就不贴了，实在需要的话留言，我再填坑。

#include <cstdio>
#include <cstring>
#include <algorithm>
#define N 101000
#define T 26
using namespace std;
int pa[N<<1],son[N<<1][T];
int deep[N<<1],cnt,root,last;
char str[N];
inline int Newnode(int _deep){deep[++cnt]=_deep;return cnt;}
inline void SAM(int alp)
{
	int np=Newnode(deep[last]+1);
	int u=last;
	while(u&&!son[u][alp])son[u][alp]=np,u=pa[u];
	if(!u)pa[np]=root;
	else 
	{
		int v=son[u][alp];
		if(deep[v]==deep[u]+1)pa[np]=v;
		else 
		{
			int nv=Newnode(deep[u]+1);
			memcpy(son[nv],son[v],sizeof(son[v]));
			pa[nv]=pa[v],pa[v]=pa[np]=nv;
			while(u&&son[u][alp]==v)son[u][alp]=nv,u=pa[u];
		}
	}
	last=np;
}
inline void pre(){root=last=Newnode(0);}
int main()
{
	freopen("test.in","r",stdin);
	scanf("%s",str);
	pre();
	for(int i=0;str[i];i++)SAM(str[i]-'a');
	return 0;
}

后缀自动机，SAM，suffix automaton 模板