poj 2774

传送门:http://poj.org/problem?id=2774

裸的后缀数组,我只是为了贴个版而已

代码

#include <cstdio>
#include <cmath>
#include <iostream>
#include <cstring>
#include <algorithm>
#define ll long long
#define mod 1000000007
using namespace std;
int s[200005],wa[200005],wb[200005],ws1[200005],sz[200005],wv[200005],rank[200005],sa[200005],height[200005];
char s1[200005],s2[200005];
bool cmp(int *x,int a,int b,int k)
{
    return (x[a]==x[b])&&(x[a+k]==x[b+k]);
}
void getsa(int *r,int *sa,int n,int m)
{
    int i,j,p,*x=wa,*y=wb,*t;
    for (i=0;i<m;i++) ws1[i]=0;
    for (i=0;i<n;i++) ws1[x[i]=r[i]]++;
    for (i=1;i<m;i++) ws1[i]+=ws1[i-1];
    for (i=n-1;i>=0;i--) sa[--ws1[x[i]]]=i;
    for (j=1,p=1;p<n;j*=2,m=p)
    {
        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<n;i++) wv[i]=x[y[i]];
        for (i=0;i<m;i++) ws1[i]=0;
        for (i=0;i<n;i++) ws1[wv[i]]++;
        for (i=1;i<m;i++) ws1[i]+=ws1[i-1];
        for (i=n-1;i>=0;i--) sa[--ws1[wv[i]]]=y[i];
        t=x;x=y;y=t;
        x[sa[0]]=0;
        for (p=1,i=1;i<n;i++)
        {
            x[sa[i]]=cmp(y,sa[i-1],sa[i],j)?p-1:p++;
        }
    }
    return;
}
void getans(int *r,int n)
{
    int i,j,k=0;
    for (i=1;i<=n;i++) rank[sa[i]]=i;
    for (i=0;i<n;i++)
    {
        if (k) k--;
        else k=0;
        j=sa[rank[i]-1];
        while (r[i+k]==r[j+k])
        {
            k++;
        }
        height[rank[i]]=k;
    }
    return;
}
int main()
{
    while (~scanf("%s",s1))
    {
        int t=0;

        scanf("%s",s2);
        int len=strlen(s1);
        int x1=0;
        for (int i=0;i<len;i++)
        s[x1++]=s1[i]-'a'+1;
        s[x1++]=28;
        len=strlen(s2);
        for (int i=0;i<len;i++)
        s[x1++]=s2[i]-'a'+1;
        s[x1]=0;
        getsa(s,sa,x1+1,30);
        getans(s,x1);
        int ans=0;
        len=strlen(s1);
        for (int i=2;i<x1;i++)
        if(height[i]>ans)
        {
            if(0<=sa[i-1]&&sa[i-1]<len&&len<sa[i])
            ans=height[i];
            if(0<=sa[i]&&sa[i]<len&&len<sa[i-1])
            ans=height[i];
        }
        printf("%d\n",ans);
    }
}