poj 3294 后缀数组

#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;
const int maxn=200000;

int s[maxn],w[maxn],wa[maxn],wb[maxn],x[maxn],y[maxn],sa[maxn],rk[maxn];
int v[maxn],tp[maxn],h[maxn];
char st[1500];
int nn,n,m,ans;

int cmp(int* r,int a,int b,int l)
{
return r[a]==r[b] && r[a+l]==r[b+l];
}

void da(int* s,int* sa,int n,int m)
{
int i,j,p,*x=wa,*y=wb,*t;
for (i=0;i<m;i++) w[i]=0;
for (i=0;i<n;i++) w[x[i]=s[i]]++;
for (i=1;i<m;i++) w[i]+=w[i-1];
for (i=n-1;i>=0;i--) sa[--w[x[i]]]=i;
for (j=1,p=1;p<n;m=p,j*=2)
{
for (p=0,i=n-j;i<n;i++) y[p++]=i;
for (i=0;i<n;i++) if (sa[i]>=j) y[p++]=sa[i]-j;
for (i=0;i<m;i++) w[i]=0;
for (i=0;i<n;i++) v[i]=x[y[i]];
for (i=0;i<n;i++) w[v[i]]++;
for (i=1;i<m;i++) w[i]+=w[i-1];
for (i=n-1;i>=0;i--) sa[--w[v[i]]]=y[i];
for (t=x,x=y,y=t,p=1,x[sa[0]]=0,i=1;i<n;i++)
x[sa[i]]=cmp(y,sa[i-1],sa[i],j)?p-1:p++;
}
}

void calheight()
{
int i,j,k=0;
for (i=1;i<=n;i++) rk[sa[i]]=i;
for (i=0;i<n;h[rk[i++]]=k)
for (k?k--:0,j=sa[rk[i]-1];s[i+k]==s[j+k];k++);
}

bool ok(int mid)
{
bool v[105]={0};
int tot=0,i;
for (i=1;i<=n;i++)
{
if (h[i]<mid)
{
memset(v,0,sizeof(v));
v[tp[sa[i]]]=true;
tot=1;
}
else if (!v[tp[sa[i]]])
{
v[tp[sa[i]]]=true;
tot++;
}
if (tot>nn/2) return true;
}
return false;
}

int work()
{
int ll=1,rr=1000,mid,ans=0;
while (ll<=rr)
{
mid=(ll+rr)/2;
if (ok(mid)) ans=mid,ll=mid+1;
else rr=mid-1;
}
return ans;
}

void print(int ans)
{
int tot=0,i,j;
bool v[105]={0};
for (i=1;i<=n;i++)
{
if (h[i]<ans)
{
if (tot>nn/2)
{
for (j=0;j<ans;j++)
printf("%c",s[sa[i-1]+j]);
printf("\n");
}
memset(v,0,sizeof(v));
v[tp[sa[i]]]=true;
tot=1;
}
else if (!v[tp[sa[i]]])
{
v[tp[sa[i]]]=true;
tot++;
}
}
}

int main()
{
freopen("pin.txt","r",stdin);
freopen("pou.txt","w",stdout);
int i,j,t=0;
while (1)
{
scanf("%d",&nn);
if (nn==0) break;
if (t) printf("\n");
t=1;
n=0;
for (i=1;i<=nn;i++)
{
scanf("%s",st);
for (j=0;j<strlen(st);j++)
{
s
=st[j];
tp[n++]=i;
}
if (i==nn) break;
s
=i+200;tp[n++]=0;
}
s
=0;
da(s,sa,n+1,400);
calheight();
ans=work();
if (ans==0) printf("?\n");
else print(ans);
}
return 0;
}