1 #include<cstdio> 2 #include<cstdlib> 3 #include<cmath> 4 #include<cstring> 5 #include<algorithm> 6 #include<iostream> 7 #include<vector> 8 #include<map> 9 #include<set>10 #include<queue>11 #include<string>12 #define inf 100000000013 #define maxn 10000014 #define maxm 500+10015 #define eps 1e-1016 #define ll long long17 #define pa pair<int,int>18 #define for0(i,n) for(int i=0;i<=(n);i++)19 #define for1(i,n) for(int i=1;i<=(n);i++)20 #define for2(i,x,y) for(int i=(x);i<=(y);i++)21 #define for3(i,x,y) for(int i=(x);i>=(y);i--)22 #define mod 100000000723 using namespace std;24 inline int read()25 {26     int x=0,f=1;char ch=getchar();27     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}28     while(ch>=‘0‘&&ch<=‘9‘){x=10*x+ch-‘0‘;ch=getchar();}29     return x*f;30 }31 int n,m,c[maxn],t1[maxn],t2[maxn],sa[maxn],rk[maxn],h[maxn],a[maxn];32 char s[maxn];33 bool v[10];34 void getsa(int m)35 {36     int *x=t1,*y=t2;37     for0(i,m)c[i]=0;38     for0(i,n)c[x[i]=s[i]]++;39     for1(i,m)c[i]+=c[i-1];40     for3(i,n,0)sa[--c[x[i]]]=i;41     for(int k=1;k<=n+1;k<<=1)42     {43         int p=0;44         for2(i,n-k+1,n)y[p++]=i;45         for0(i,n)if(sa[i]>=k)y[p++]=sa[i]-k;46         for0(i,m)c[i]=0;47         for0(i,n)c[x[y[i]]]++;48         for1(i,m)c[i]+=c[i-1];49         for3(i,n,0)sa[--c[x[y[i]]]]=y[i];50         swap(x,y);p=0;x[sa[0]]=0;51         for1(i,n)x[sa[i]]=y[sa[i]]==y[sa[i-1]]&&y[sa[i]+k]==y[sa[i-1]+k]?p:++p;52         if(p>=n)break;53         m=p;54     }55     for1(i,n)rk[sa[i]]=i;56     for(int i=0,k=0,j;i<n;h[rk[i++]]=k)57      for(k?k--:0,j=sa[rk[i]-1];s[i+k]==s[j+k];k++);58 }    59 bool check(int x)60 {61     for(int i=1,j=1;j<=n+1;j++)62      if(h[j]<x||j==n+1)63       {64           for1(k,m)v[k]=0;65           for2(k,i,j-1)v[a[sa[k]]]=1;66           bool flag=0;67           for1(k,m)if(!v[k])flag=1;68           if(!flag)return 1;69           i=j;70       }71     return 0;72 }73 int main()74 {75     freopen("input.txt","r",stdin);76     freopen("output.txt","w",stdout);77     m=read();78     for1(i,m)79     {80         s[n]=‘z‘+i;81         scanf("%s",s+n+1);82         int t=strlen(s);for2(j,n+1,t-1)a[j]=i;83         n=t;84     }85     s[n]=‘ ‘;86     getsa(128);87     int l=0,r=n,mid;88     while(l<=r)89     {90         mid=(l+r)>>1;91         if(check(mid))l=mid+1;else r=mid-1;92     }93     printf("%d\n",r);94     return 0;95 }