[后缀数组 set] BZOJ 4516 [Sdoi2016]生成魔咒

#include<cstdio>
#include<cstdlib>
#include<algorithm>
#include<set>
using namespace std;
typedef long long ll;

inline char nc()
{
static char buf[100000],*p1=buf,*p2=buf;
if (p1==p2) { p2=(p1=buf)+fread(buf,1,100000,stdin); if (p1==p2) return EOF; }
return *p1++;
}

inline void read(int &x)
{
char c=nc(),b=1;
for (;!(c>='0' && c<='9');c=nc()) if (c=='-') b=-1;
for (x=0;c>='0' && c<='9';x=x*10+c-'0',c=nc()); x*=b;
}

const int N=100005;

int sx
,icnt;

inline int Bin(int x)
{
return lower_bound(sx+1,sx+icnt+1,x)-sx;
}

int n,a
;
int sa
,t1
,t2
,c
;
int height
,rank
;

inline void SA(int *r,int m)
{
int *x=t1,*y=t2;
for (int i=0;i<=m;i++) c[i]=0;
for (int i=1;i<=n;i++) c[x[i]=r[i]]++;
for (int i=1;i<=m;i++) c[i]+=c[i-1];
for (int i=n;i;i--) sa[c[x[i]]--]=i;
for (int k=1;k<=n;k<<=1)
{
int p=0;
for (int i=n-k+1;i<=n;i++) y[++p]=i;
for (int i=1;i<=n;i++) if (sa[i]>k) y[++p]=sa[i]-k;
for (int i=0;i<=m;i++) c[i]=0;
for (int i=1;i<=n;i++) c[x[y[i]]]++;
for (int i=1;i<=m;i++) c[i]+=c[i-1];
for (int i=n;i;i--) sa[c[x[y[i]]]--]=y[i];
swap(x,y);
x[sa[1]]=1; p=1;
for (int i=2;i<=n;i++)
x[sa[i]]=(y[sa[i]]==y[sa[i-1]] && y[sa[i]+k]==y[sa[i-1]+k])?p:++p;
if (p>=n) break;
m=p;
}
}

inline void GetHeight(int *S,int *sa,int n)
{
int j,k=0;
for (int i=1;i<=n;i++) rank[sa[i]]=i;
for (int i=1;i<=n;height[rank[i++]]=k)
for (k?k--:0,j=sa[rank[i]-1];S[i+k]==S[j+k];)
k++;
}

namespace ST{
int st
[20],Log
;
inline void Build(int n,int *a){
for (int i=2;i<=n;i++) Log[i]=Log[i>>1]+1;
for (int i=1;i<=n;i++)
st[i][0]=a[i];
for (int k=1;k<20;k++)
for (int i=1;i<=n;i++)
{
st[i][k]=st[i][k-1];
if (i+(1<<(k-1))<=n)
st[i][k]=min(st[i][k],st[i+(1<<(k-1))][k-1]);
}
}
inline int Query(int l,int r){
int t=Log[r-l+1];
return min(st[l][t],st[r-(1<<t)+1][t]);
}
}

set<int> Set;
typedef set<int>::iterator ITER;
int pre
,nxt
;
ll ans,cnt
;

inline int Height(int x,int y){
return ST::Query(x+1,y);
}

int main()
{
int p,now;
freopen("t.in","r",stdin);
freopen("t.out","w",stdout);
read(n);
for (int i=1;i<=n;i++)
read(a[i]),sx[++icnt]=a[i];
reverse(a+1,a+n+1);
sort(sx+1,sx+icnt+1);
icnt=unique(sx+1,sx+icnt+1)-sx-1;
for (int i=1;i<=n;i++) a[i]=Bin(a[i]);
SA(a,icnt);
GetHeight(a,sa,n);
ST::Build(n,height);
Set.insert(0);
for (int i=n;i;i--)
{
now=rank[i];
ITER it=Set.upper_bound(now);
if (it!=Set.end())
{
p=*it;
ans-=cnt[p];
cnt[p]=(n-sa[p]+1)-Height(now,p);
ans+=cnt[p];
}
p=*(--it);
cnt[now]=(n-i+1)-Height(p,now);
Set.insert(now);;
ans+=cnt[now];
printf("%lld\n",ans);
}
return 0;
}