BZOJ 4698: Sdoi2008 Sandy的卡片 [后缀自动机]

4698: Sdoi2008 Sandy的卡片

题意：差分后就是多个串LCS

---

SAM+map大法好

模板打错 智力-2

#include <iostream>

#include <cstdio>

#include <cstring>

#include <algorithm>

#include <cmath>

#include <map>

using namespace std;

typedef long long ll;

const int N=2005;

inline int read(){

    char c=getchar();int x=0,f=1;

    while(c<'0'||c>'9'){if(c=='-')f=-1;c=getchar();}

    while(c>='0'&&c<='9'){x=x*10+c-'0';c=getchar();}

    return x*f;

}

namespace sam{

	struct meow{map<int, int> ch; int par, val;} t[N];

	int sz=1, last=1, root=1;

void extend(int c) {

	int p=last, np=++sz; t[np].val=t[p].val+1;

	for(; p && !t[p].ch[c]; p=t[p].par) t[p].ch[c]=np;

	if(!p) t[np].par = root;

	else {

		int q = t[p].ch[c];

		if(t[q].val == t[p].val+1) t[np].par = q;

		else {

			int nq = ++sz; t[nq]=t[q]; t[nq].val=t[p].val+1;

			t[q].par = t[np].par = nq;

			for(; p && t[p].ch[c]==q; p=t[p].par) t[p].ch[c] = nq;

		}

	}

	last=np;

}

	int c[N], a[N], ans[N];

	void RadixSort() {

		for(int i=0; i<=sz; i++) c[i]=0;

		for(int i=1; i<=sz; i++) c[t[i].val]++;

		for(int i=1; i<=sz; i++) c[i] += c[i-1];

		for(int i=sz; i>=1; i--) a[ c[t[i].val]-- ]=i;

		for(int i=1; i<=sz; i++) ans[i] = t[i].val;

	}

	int f[N]; // max lenth

	void solve(int *s, int n) { //puts("\n solve");

		int u=root, now=0;

		for(int i=1; i<=n; i++) {

			int c = s[i]; //printf("i %d  %d\n",i,c);

			if(t[u].ch.count(c)) u=t[u].ch[c], f[u] = max(f[u], ++now);

			else {

				while(u && !t[u].ch.count(c)) u=t[u].par;

				if(!u) u=root, now=0;

				else now=t[u].val, u=t[u].ch[c], f[u] = max(f[u], ++now);

			}

		}

		for(int i=sz; i>=1; i--) {

			int u=a[i]; ans[u] = min(ans[u], f[u]); //printf("f %d %d\n",u,f[u]);

			if(f[u] && t[u].par) f[t[u].par] = t[t[u].par].val;

			f[u]=0;

		}

	}

}

int n, len, s[N], last, x;

int main() {

	freopen("in","r",stdin);

	n=read();

	len=read(); last=read();

	for(int i=1; i<len; i++) x=read(), s[i]=x-last, last=x;

	len--;

	for(int i=1; i<=len; i++) sam::extend(s[i]);

	sam::RadixSort();

	for(int i=2; i<=n; i++) {

		len=read(); last=read();

		for(int i=1; i<len; i++) x=read(), s[i]=x-last, last=x;

		len--;

		sam::solve(s, len);

	}

	int ans=0;

	for(int i=2; i<=sam::sz; i++) ans = max(ans, sam::ans[i]);

	printf("%d", ans+1);

}