BZOJ 1396:识别子串 SA+树状数组+单调队列

#include<cstdio>
#include<cmath>
#include<cstring>
#include<algorithm>
const int len(100000),limt(255);
int str[len+10],sfa[len+10],rank[len+10],height[len+10];
int tmp[len+10],p[len+10],cnt[len+10];
int n,c[len+10],ans[len+10],q[len+10],li,hi;char ch[len+10];
struct data{int x,y;}h[len+10];
int max(int a,int b){return a>b?a:b;}
int min(int a,int b){return a<b?a:b;}
bool com(int x,int y,int l){return (rank[x]==rank[y])&&(rank[x+l]==rank[y+l]);}
void doubling()
{
	for(int i=1;i<=n;i++){rank[i]=str[i];sfa[i]=i;}
	for(int pos=0,l=0,sigma=limt;pos<n;sigma=pos)
	{
		pos=0;
		for(int i=n-l+1;i<=n;i++)p[++pos]=i;
		for(int i=1;i<=n;i++)if(sfa[i]>l)p[++pos]=sfa[i]-l;
		memset(cnt,0,sizeof(int)*(sigma+1));pos=0;
		for(int i=1;i<=n;i++)cnt[rank[i]]++;
		for(int i=1;i<=sigma;i++)cnt[i]+=cnt[i-1];
		for(int i=n;i>=1;i--)sfa[cnt[rank[p[i]]]--]=p[i];
		for(int i=1;i<=n;i++)tmp[sfa[i]]=com(sfa[i],sfa[i-1],l)?pos:++pos;
		for(int i=1;i<=n;i++)rank[i]=tmp[i];
		l=!l?1:l<<1;
	}
	for(int i=1;i<=n;i++)rank[sfa[i]]=i;
	for(int i=1,k,j;i<=n;i++)
	{
		k=sfa[rank[i]-1];
		if(!k)continue;
		j=height[rank[i-1]];
		if(j)j--;
		while(str[i+j]==str[k+j])j++;
		height[rank[i]]=j;
	}
}
int query(int x){int sum=0;for(;x;x-=x&(-x))sum=max(sum,c[x]);return sum;}
void put(int x,int y){for(;x<=n;x+=x&(-x))c[x]=max(c[x],y);}
int main()
{
	freopen("C.in","r",stdin);
	freopen("C.out","w",stdout);
	scanf("%s",ch);n=strlen(ch);
	for(int i=1;i<=n;i++)str[i]=ch[i-1]-‘a‘+1;
	doubling();
	for(int i=1;i<=n;i++)
	{
		h[i].x=i+max(height[rank[i]],height[rank[i]+1]);
		h[i].y=i;
		if(h[i].x>n+1)printf("NO");
	}
	for(int i=1,t;i<=n;i++)
	{
		if(h[i].x!=n+1)ans[h[i].y]=h[i].x-h[i].y+1;
		else ans[h[i].y]=n;
		t=query(h[i].y);
		if(t)ans[h[i].y]=min(h[i].y-t+1,ans[h[i].y]);
		if(h[i].x!=n+1)put(h[i].x,h[i].y);
	}
	q[li=1]=1;hi=1;
	for(int i=2;i<=n;i++)
	{
		while(h[q[hi]].x<i&&hi<=li)hi++;
		if(hi<=li&&h[q[hi]].x>=i&&h[q[hi]].x!=n+1)ans[h[i].y]=min(ans[h[i].y],h[q[hi]].x-h[q[hi]].y+1);
		if(h[i].x!=n+1)
		{
			while(h[q[li]].x-h[q[li]].y>h[i].x-h[i].y&&li>=hi)li--;
			q[++li]=i;
		}
	}
	for(int i=1;i<=n;i++)printf("%d\n",ans[i]);
	return 0;
}