acdream 1430 SETI 后缀数组+height分组

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<map>
#include<queue>
#include<set>
#include<cmath>
#include<bitset>
#define mem(a,b) memset(a,b,sizeof(a))
#define lson i<<1,l,mid
#define rson i<<1|1,mid+1,r
#define llson j<<1,l,mid
#define rrson j<<1|1,mid+1,r
#define INF 0x7fffffff
#define seed 13131
#define seed1 1313
#define maxn 20005
typedef long long ll;
typedef unsigned long long ull;
using namespace std;
void radix(int *str,int *a,int *b,int n,int m)
{
static int count[maxn];
mem(count,0);
for(int i=0; i<n; i++) ++count[str[a[i]]];
for(int i=1; i<=m; i++) count[i]+=count[i-1];
for(int i=n-1; i>=0; i--) b[--count[str[a[i]]]]=a[i];
}
void suffix(int *str,int *sa,int n,int m) //倍增算法计算出后缀数组sa
{
static int rank[maxn],a[maxn],b[maxn];
for(int i=0; i<n; i++) rank[i]=i;
radix(str,rank,sa,n,m);
rank[sa[0]]=0;
for(int i=1; i<n; i++)
rank[sa[i]]=rank[sa[i-1]]+(str[sa[i]]!=str[sa[i-1]]);
for(int i=0; 1<<i<n; i++)
{
for(int j=0; j<n; j++)
{
a[j]=rank[j]+1;
b[j]=j+(1<<i)>=n?0:rank[j+(1<<i)]+1;
sa[j]=j;
}
radix(b,sa,rank,n,n);
radix(a,rank,sa,n,n);
rank[sa[0]]=0;
for(int j=1; j<n; j++)
rank[sa[j]]=rank[sa[j-1]]+(a[sa[j-1]]!=a[sa[j]]||b[sa[j-1]]!=b[sa[j]]);
}
}
void calcHeight(int *str,int *sa,int *h,int *rank,int n) //求出最长公共前缀数组h
{
int k=0;
h[0]=0;
for(int i=0; i<n; i++) rank[sa[i]]=i;
for(int i=0; i<n; i++)
{
k=k==0?0:k-1;
if(rank[i])
while(str[i+k]==str[sa[rank[i]-1]+k]) k++;
else k=0;
h[rank[i]]=k;
}
}
int a[maxn],sa[maxn],height[maxn],rank[maxn];
char s[maxn];
int main()
{
//freopen("1.txt","r",stdin);
scanf("%s",s);
int n=strlen(s);
copy(s,s+n,a);
suffix(a,sa,n,150);
calcHeight(a,sa,height,rank,n);
int Max,Min,sum=0;
for(int i=1;i<=n/2;i++)
{
Max=Min=sa[0];
for(int j=1;j<=n;j++)
{
if(height[j]<i||j==n)
{
if(Max-Min>=i) sum++;
Max=Min=sa[j];
}
else
{
Max=max(Max,sa[j]);
Min=min(Min,sa[j]);
}
}
}
printf("%d\n",sum);
return 0;
}