P7456 [CERC2018] The ABCD Murderer (ac自动机+线段树优化dp/反向st）

做法

ac自动机预处理出最长后缀
f[i]=max(f[i-1],f[i-2],…,f[i-最长后缀])+1;
转移即可
下面有一种反向st维护的学到了

#include 
using namespace  std;
//#define  int long long
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef vector<int> vi;
#define fi first
#define se second
#define pb  push_back
#define inf 1<<62
#define endl "\n"
#define max(a,b) ((a)>(b)?(a):(b))
#define min(a,b) ((a)<(b)?(a):(b))
#define de_bug(x) cerr << #x << "=" << x << endl
#define all(a) a.begin(),a.end()
#define IOS   std::ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define  fer(i,a,b)  for(int i=a;i<=b;i++)
#define  der(i,a,b)  for(int i=a;i>=b;i--)
const int mod = 1e9 + 7;
const int N = 5e5 + 10;
const int M = 3e5 + 10;
int n, m;
struct node {
	int l, r;
	int s;
} tr[N * 4];
#define ls i*2
#define rs i*2+1
void build(int i, int l, int r) {
	tr[i] = {l, r, 1 << 30};
	if(l == r)return ;
	int mid = l + r >> 1;
	build(ls, l, mid);
	build(rs, mid + 1, r);
}
void push_up(int i) {
	tr[i].s = min(tr[ls].s, tr[rs].s);
}
void change(int i, int x, int val) {
	if(tr[i].l == tr[i].r) {
		tr[i].s = min(tr[i].s, val);
		return ;
	}
	int mid = (tr[i].l + tr[i].r) >> 1;
	if(x <= mid) change(ls, x, val);
	else  change(rs, x, val);
	push_up(i);
}
int query(int i, int l, int r) {
	if(l <= tr[i].l && tr[i].r <= r) {
		return tr[i].s;
	}
	int mid = (tr[i].l + tr[i].r) >> 1;
	int ans = 1 << 30;
	if(l <= mid) ans = min(ans, query(ls, l, r));
	if(r > mid) ans = min(ans, query(rs, l, r));
	return ans;
}
struct acam {
	struct node {
		int fail;
		int f = 0;
		int son[26] = {};
	} trie[N];
	int ma[N];
	int idx = 0;
	void insert(string &s) {
		int u = 0;
		for(auto c : s) {
			if(!trie[u].son[c - 'a']) {
				trie[u].son[c - 'a'] = ++idx;
			}
			u = trie[u].son[c - 'a'];
		}
		ma[u] = s.size();
	}

	void build() {
		queue<int>q;
		for(int i = 0; i <= 25; i++) {
			if(trie[0].son[i]) {
				q.push(trie[0].son[i]);
			}
		}
		while(!q.empty()) {
			int u = q.front();
			q.pop();
			ma[u] = max(ma[u] , ma[trie[u].fail] );
			for(int i = 0; i <= 25; i++) {
				int v = trie[u].son[i], fa = trie[trie[u].fail].son[i];
				if(trie[u].son[i]) {
					trie[v].fail = fa;
					q.push(v);
				} else {
					trie[u].son[i] = trie[trie[u].fail].son[i];
				}
			}

		}

	}
	void get(string &s) {
		int u = 0;
		for(int i = 1; i < s.size(); i++) {
			int v = s[i] - 'a';
			u = trie[u].son[v];
			int l = max(0, i - ma[u]), r = i - 1;
			if(l > r)continue;
			change(1, i, query(1, l, r) + 1);
		}
	}
} AC;
string s;
void solve() {
	cin >> n;
	cin >> s;
	m = s.size();
	s = " " + s;
	for(int i = 1; i <= n; i++) {
		string t;
		cin >> t;
		AC.insert(t);
	}
	AC.build();
	build(1, 0, m);
	change(1, 0, 0);
	AC.get(s);
	int ans = query(1, m, m);
	if(ans >= (1 << 30))ans = -1;
	 cout << ans << endl;

}


int main() {
	IOS;
	int _ = 1;
	//cin>>_;
	while( _-- )
		solve();
}





反向st表
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#include 
using namespace  std;
//#define  int long long
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef vector<int> vi;
#define fi first
#define se second
#define pb  push_back
#define inf 1<<62
#define endl "\n"
#define max(a,b) ((a)>(b)?(a):(b))
#define min(a,b) ((a)<(b)?(a):(b))
#define de_bug(x) cerr << #x << "=" << x << endl
#define all(a) a.begin(),a.end()
#define IOS   std::ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define  fer(i,a,b)  for(int i=a;i<=b;i++)
#define  der(i,a,b)  for(int i=a;i>=b;i--)
const int mod = 1e9 + 7;
const int N = 5e5 + 10;
const int M = 3e5 + 10;
int n, m;

struct acam {
	struct node {
		int fail;
		int f = 0;
		int son[26] = {};
	} trie[N];
	int ma[N];
	int idx = 0;
	void insert(string &s) {
		int u = 0;
		for(auto c : s) {
			if(!trie[u].son[c - 'a']) {
				trie[u].son[c - 'a'] = ++idx;
			}
			u = trie[u].son[c - 'a'];
		}
		ma[u] = s.size();
	}

	void build() {
		queue<int>q;
		for(int i = 0; i <= 25; i++) {
			if(trie[0].son[i]) {
				q.push(trie[0].son[i]);
			}
		}
		while(!q.empty()) {
			int u = q.front();
			q.pop();
			ma[u] = max(ma[u] , ma[trie[u].fail] );
			for(int i = 0; i <= 25; i++) {
				int v = trie[u].son[i], fa = trie[trie[u].fail].son[i];
				if(trie[u].son[i]) {
					trie[v].fail = fa;
					q.push(v);
				} else {
					trie[u].son[i] = trie[trie[u].fail].son[i];
				}
			}

		}

	}

} AC;
int  dp[N][22];
int query(int l, int r) {
	if(l > r)return 1e9 + 7;
	int k = log2(r - l + 1);
	return min(dp[r][k], dp[l + (1 << k) - 1][k]);
}
string s;
void solve() {
	cin >> n;
	cin >> s;
	m = s.size();
	s = " " + s;
	for(int i = 1; i <= n; i++) {
		string t;
		cin >> t;
		AC.insert(t);
	}
	AC.build();
	memset(dp, 0x3f, sizeof(dp));
	int u = 0;
	dp[0][0] = 0;
	for(int i = 1; i <= m; i++) {
		u = AC.trie[u].son[s[i] - 'a'];
		dp[i][0] = query( i - AC.ma[u], i - 1) + 1;
		for(int j = 1; j < 20; j++) {
			if(i - (1 << j) + 1 < 0)break;
			dp[i][j] = min(dp[i][j - 1], dp[i - (1 << j - 1) ][j - 1]);
		}
	}
	int  ans;
	if(dp[m][0] >= 1e9 + 7)ans = -1;
	else ans = dp[m][0];
	cout << ans << endl;


}


int main() {
	IOS;
	int _ = 1;
	//cin>>_;
	while( _-- )
		solve();
}






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