洛谷 P2414 / LOJ 2444 「NOI2011」阿狸的打字机

/*

p_b_p_b txdy
AThousandMoon txdy
AThousandSuns txdy
hxy txdy

*/

#include <bits/stdc++.h>
#define pb push_back
#define fst first
#define scd second

using namespace std;
typedef long long ll;
typedef pair<int, int> pii;

const int maxn = 100100;

int n, m, a[maxn], ans[maxn];
int c[maxn], st[maxn], ed[maxn], times;
int head[maxn], len;
char s[maxn];
vector<pii> qq[maxn];

struct edge {
	int to, next;
} edges[maxn << 1];

void add_edge(int u, int v) {
	edges[++len].to = v;
	edges[len].next = head[u];
	head[u] = len;
}

inline int lowbit(int x) {
	return x & (-x);
}

inline void update(int x, int d) {
	for (int i = x; i <= times; i += lowbit(i)) {
		c[i] += d;
	}
}

inline int query(int x) {
	int res = 0;
	for (int i = x; i; i -= lowbit(i)) {
		res += c[i];
	}
	return res;
}

struct AC {
	int ch[maxn][26], och[maxn][26], fa[maxn];
	int fail[maxn], tot;
	
	void insert(char *s) {
		int p = 0;
		for (int i = 0; s[i]; ++i) {
			if (islower(s[i])) {
				if (!ch[p][s[i] - 'a']) {
					ch[p][s[i] - 'a'] = ++tot;
					fa[tot] = p;
				}
				p = ch[p][s[i] - 'a'];
			} else if (s[i] == 'B') {
				p = fa[p];
			} else {
				a[++n] = p;
			}
		}
		for (int i = 0; i <= tot; ++i) {
			for (int j = 0; j < 26; ++j) {
				och[i][j] = ch[i][j];
			}
		}
	}
	
	void build() {
		queue<int> q;
		for (int i = 0; i < 26; ++i) {
			if (ch[0][i]) {
				q.push(ch[0][i]);
			}
		}
		while (q.size()) {
			int u = q.front();
			q.pop();
			for (int i = 0; i < 26; ++i) {
				if (ch[u][i]) {
					fail[ch[u][i]] = ch[fail[u]][i];
					q.push(ch[u][i]);
				} else {
					ch[u][i] = ch[fail[u]][i];
				}
			}
		}
	}
	
	void dfs(int u) {
		st[u] = ++times;
		for (int i = head[u]; i; i = edges[i].next) {
			int v = edges[i].to;
			dfs(v);
		}
		ed[u] = times;
	}
	
	void dfs2(int u) {
		update(st[u], 1);
		for (pii p : qq[u]) {
			ans[p.scd] = query(ed[p.fst]) - query(st[p.fst] - 1);
		}
		for (int i = 0; i < 26; ++i) {
			if (och[u][i]) {
				dfs2(och[u][i]);
			}
		}
		update(st[u], -1);
	}
	
	void solve() {
		for (int i = 1; i <= tot; ++i) {
			add_edge(fail[i], i);
		}
		dfs(0);
		dfs2(0);
		for (int i = 1; i <= m; ++i) {
			printf("%d\n", ans[i]);
		}
	}
} ac;

void solve() {
	scanf("%s%d", s, &m);
	ac.insert(s);
	ac.build();
	for (int i = 1; i <= m; ++i) {
		int x, y;
		scanf("%d%d", &x, &y);
		qq[a[y]].pb(make_pair(a[x], i));
	}
	ac.solve();
}

int main() {
	int T = 1;
	// scanf("%d", &T);
	while (T--) {
		solve();
	}
	return 0;
}