poj3405 Corporate Identity

和上一个1226一样吧，这个还不用翻转

然而本蒟蒻还是写不对，WA一片天，不知道自己搞什么，自从去了长沙感觉就是坑啊

while(1) iq--;

/*#include <cstdio>
#include <iostream>
#include <cstring>
#define N 100005
#define LL long long
#define eps 1e-8
using namespace std;
inline int ra()
{
    int x=0,f=1; char ch=getchar();
    while (ch<'0' || ch>'9') {if (ch=='-') f=-1; ch=getchar();}
    while (ch>='0' && ch<='9') {x=x*10+ch-'0'; ch=getchar();}
    return x*f;
}

const int M=4233;
const int maxn=4000*233*3;

int sa[2][maxn],rank[2][maxn],height[maxn],v[M+5];
char ans[205];
int n,len,id[maxn],p,q,a[maxn];
bool vis[M];

void cal_sa(int sa[maxn], int rank[maxn], int Sa[maxn], int Rank[maxn], int k)
{
    for (int i=1; i<=n; i++) v[rank[sa[i]]]=i;
    for (int i=n; i>=1; i--) if (sa[i]>k) Sa[v[rank[sa[i]-k]]--]=sa[i]-k;
    for (int i=n-k+1; i<=n; i++) Sa[v[rank[i]]--]=i;
    for (int i=1; i<=n; i++) Rank[Sa[i]]=Rank[Sa[i-1]]+(rank[Sa[i]]!=rank[Sa[i-1]] || rank[Sa[i]+k]!=rank[Sa[i-1]+k]);
}
void get_height()
{
    int k=0;
    for (int i=1; i<=n; i++)
    {
        if (rank[p][i]==1) height[1]=0;
        else
        {
            int j=sa[p][rank[p][i]-1];
            while (a[j+k]==a[i+k]) k++;
            height[rank[p][i]]=k;
            if (k) k--;
        }
    }
}
void work()
{
    for (int i=1; i<=n; i++) v[a[i]]++;
    for (int i=1; i<=M; i++) v[i]+=v[i-1];
    for (int i=1; i<=n; i++) sa[p][v[a[i]]--]=i;
    for (int i=1; i<=n; i++) rank[p][sa[p][i]]=rank[p][sa[p][i-1]]+(a[sa[p][i]]!=a[sa[p][i-1]]);
    for (int k=1; k<n; k<<=1,swap(p,q)) cal_sa(sa[p],rank[p],sa[q],rank[q],k);
    get_height();
}
bool check(int L)
{
    int cnt=0;
    memset(vis,0,sizeof(vis));
    for (int i=2; i<=n; i++)
    {
        if (height[i]<L) 
        {
            cnt=0;
            memset(vis,0,sizeof(vis));
            continue;
        }
        if (!vis[id[sa[p][i-1]]]) vis[id[sa[p][i-1]]]=1,cnt++;
        if (!vis[id[sa[p][i]]]) vis[id[sa[p][i]]]=1,cnt++;
        if (cnt==len)
        {
            for (int j=0; j<L; j++)
                ans[j]=a[sa[p][i]+j];
            return 1;
        }
    }
    return 0;
}
int main(int argc, char const *argv[])
{
    while (scanf("%d",&n) && n)
    {
        len=0;
        memset(v,0,sizeof(v));
        for (int i=1; i<=n; i++)
        {
            char ch[205]; 
            scanf("%s",ch+1);
            for (int j=1; j<=strlen(ch+1); j++) a[++len]=ch[j],id[len]=i;
            a[++len]=150+i; id[len]=i;
        }
        swap(n,len);
        work();
    //    for (int i=1; i<=n; i++) cout<<height[i]<<"  "<<id[sa[p][i]]<<endl;
        int l=1,r=205; bool flag=0;
        while (l<=r)
        {
            int mid=l+r>>1;
            if (check(mid)) flag=1,l=mid+1;
                else r=mid-1;
        }
        if (flag) printf("%s\n",ans);
            else puts("IDENTITY LOST");
    }
    return 0;
}*/




#include<cstdio>
#include<iostream>
#include<cstring>
#include<algorithm>
using namespace std;
#define maxn 888888
int t1[maxn],t2[maxn],c[maxn],sa[maxn],rank[maxn],height[maxn];
bool cmp(int *r, int a, int b, int l)
{
    return r[a]==r[b] && r[a+l]==r[b+l];
}
void da(int str[], int n, int m)
{
    n++; int *x=t1,*y=t2;
    for (int i=0; i<m; i++) c[i]=0;
    for (int i=0; i<n; i++) c[x[i]=str[i]]++;
    for (int i=1; i<m; i++) c[i]+=c[i-1];
    for (int i=n-1; i>=0; i--) sa[--c[x[i]]]=i;
    for (int j=1; j<=n; j<<=1)
    {
        int p=0;
        for (int i=n-j; i<n; i++) y[p++]=i;
        for (int i=0; i<n; i++) if (sa[i]>=j) y[p++]=sa[i]-j;
        for (int i=0; i<m; i++) c[i]=0;
        for (int i=0; i<n; i++) c[x[y[i]]]++;
        for (int i=1; i<m; i++) c[i]+=c[i-1];
        for (int i=n-1; i>=0; i--) sa[--c[x[y[i]]]]=y[i];
        swap(x,y);
        p=1; x[sa[0]]=0;
        for (int i=1; i<n; i++) x[sa[i]]=cmp(y,sa[i-1],sa[i],j)?p-1:p++;
        if (p>=n) break;
        m=p;
    } 
    int k=0; n--;
    for (int i=0; i<=n; i++) rank[sa[i]]=i;
    for (int i=0; i<n; i++)
    {
        if (k) k--;
        int j=sa[rank[i]-1];
        while (str[i+k]==str[j+k]) k++;
        height[rank[i]]=k;
    }
}
int n,res,a[maxn],id[maxn],vis[4444];
char s[222],ans[222];
int check(int k)
{
    int cnt=0;
    memset(vis,0,sizeof(vis));
    for(int i=2;i<=res;i++)
    {
        if(height[i]<k)
        {
            memset(vis,0,sizeof(vis));
            cnt=0;
            continue;
        }
        if(!vis[id[sa[i-1]]])
            vis[id[sa[i-1]]]=1,cnt++;
        if(!vis[id[sa[i]]])
            vis[id[sa[i]]]=1,cnt++;
        if(cnt==n)
        {
            for(int j=0;j<k;j++)
                ans[j]=a[sa[i]+j];
            ans[k]='\0';
            return 1;
        }
    }
    return 0;
}
int main()
{
    while(~scanf("%d",&n),n)
    {
        res=0;
        for(int i=0;i<n;i++)
        {
            scanf("%s",s);
            int len=strlen(s);
            for(int j=0;j<len;j++)
                a[res]=s[j],id[res++]=i;
            a[res]='#'+i;
            id[res++]='#'+i;
        }
        a[res]=0;
        da(a,res,5000);
        int l=1,r=strlen(s),flag=0;
        while(l<=r) 
        {
            int mid=(l+r)>>1;
            if(check(mid))
            {
                flag=1;
                l=mid+1;
            }
            else r=mid-1;
        }
        if(flag)printf("%s\n",ans);
        else printf("IDENTITY LOST\n");
    }
    return 0;
}