[后缀数组 set] BZOJ 4516 [Sdoi2016]生成魔咒

将串反过来 后缀数组 然后用set维护一个序列 插入时修改答案即可


#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[N],icnt;

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

int n,a[N];
int sa[N],t1[N],t2[N],c[N];
int height[N],rank[N];


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[N][20],Log[N];
	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[N],nxt[N];
ll ans,cnt[N];

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;
}


你可能感兴趣的:([后缀数组 set] BZOJ 4516 [Sdoi2016]生成魔咒)