#line 1 "test/aoj_2444.test.cpp"
#define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=2444"
#include <cstdint>
#include <cstdio>
#include <set>
#include <string>
#line 1 "DataStructure/foldable_deque.cpp"
/**
* @brief fold 可能両端キュー
* @author えびちゃん
*/
#include <cstddef>
#include <stack>
#include <utility>
template <typename Monoid>
class foldable_deque {
public:
using size_type = size_t;
using value_type = Monoid;
private:
std::stack<value_type> M_front, M_back;
std::stack<value_type> M_front_folded, M_back_folded;
void M_rotate_to_front() {
// precondition: M_front.empty(), M_back.size() == n > 0
// postcondition: M_front.size() == (n+1)/2, M_back.size() == n/2
size_type n = M_back.size();
std::stack<value_type>().swap(M_back_folded); // clear
std::stack<value_type> tmp;
for (size_type i = 0; i < n/2; ++i) {
tmp.push(std::move(M_back.top()));
M_back.pop();
}
while (!M_back.empty()) {
push_front(M_back.top());
M_back.pop();
}
while (!tmp.empty()) {
push_back(tmp.top());
tmp.pop();
}
}
void M_rotate_to_back() {
// precondition: M_front.size() == n > 0, M_back.empty()
// postcondition: M_front.size() == n/2, M_back.size() == (n+1)/2
size_type n = M_front.size();
std::stack<value_type>().swap(M_front_folded); // clear
std::stack<value_type> tmp;
for (size_type i = 0; i < n/2; ++i) {
tmp.push(std::move(M_front.top()));
M_front.pop();
}
while (!M_front.empty()) {
push_back(M_front.top());
M_front.pop();
}
while (!tmp.empty()) {
push_front(tmp.top());
tmp.pop();
}
}
public:
size_type size() const { return M_front.size() + M_back.size(); }
bool empty() const noexcept { return M_front.empty() && M_back.empty(); }
void push_back(value_type const& x) {
M_back.push(x);
value_type f = (M_back_folded.empty()? x: M_back_folded.top() + x);
M_back_folded.push(f);
}
void push_front(value_type const& x) {
M_front.push(x);
value_type f = (M_front_folded.empty()? x: x + M_front_folded.top());
M_front_folded.push(f);
}
template <typename... Args>
void emplace_back(Args&&... args) {
M_back.emplace(std::forward<Args>(args)...);
value_type f = (M_back_folded.empty()? M_back.top(): M_back_folded.top() + M_back.top());
M_back_folded.push(f);
}
template <typename... Args>
void emplace_front(Args&&... args) {
M_front.emplace(std::forward<Args>(args)...);
value_type f = (M_front_folded.empty()? M_front.top(): M_front.top() + M_front_folded.top());
M_front_folded.push(f);
}
void pop_back() {
if (M_back.empty()) M_rotate_to_back();
M_back.pop();
M_back_folded.pop();
}
void pop_front() {
if (M_front.empty()) M_rotate_to_front();
M_front.pop();
M_front_folded.pop();
}
value_type fold() const {
value_type res{};
if (!M_front_folded.empty()) res += M_front_folded.top();
if (!M_back_folded.empty()) res += M_back_folded.top();
return res;
}
};
#line 1 "utility/monoid/rolling_hash.cpp"
/**
* @brief ロリハの演算のモノイド
* @author えびちゃん
*/
#line 10 "utility/monoid/rolling_hash.cpp"
template <typename ModInt>
class rolling_hash_monoid {
public:
using value_type = ModInt;
private:
value_type M_x = 0, M_p = 1;
public:
rolling_hash_monoid() = default; // identity
rolling_hash_monoid(value_type const& x, value_type const& p): M_x(x), M_p(p) {};
rolling_hash_monoid& operator +=(rolling_hash_monoid const& that) {
M_x = M_x * that.M_p + that.M_x;
M_p *= that.M_p;
return *this;
}
friend bool operator ==(rolling_hash_monoid const& lhs, rolling_hash_monoid const& rhs) {
return lhs.M_x == rhs.M_x && lhs.M_p == rhs.M_p;
}
friend rolling_hash_monoid operator +(rolling_hash_monoid lhs, rolling_hash_monoid const& rhs) {
return lhs += rhs;
}
friend bool operator !=(rolling_hash_monoid const& lhs, rolling_hash_monoid const& rhs) {
return !(lhs == rhs);
}
value_type const& get() const { return M_x; }
value_type const& coefficient() const { return M_p; }
};
#line 1 "ModularArithmetic/modint.cpp"
/**
* @brief 合同算術用クラス
* @author えびちゃん
*/
#line 10 "ModularArithmetic/modint.cpp"
#include <limits>
#include <type_traits>
#line 13 "ModularArithmetic/modint.cpp"
template <intmax_t Modulo>
class modint {
public:
using value_type = typename std::conditional<
(0 < Modulo && Modulo < std::numeric_limits<int>::max() / 2), int, intmax_t
>::type;
private:
static constexpr value_type S_cmod = Modulo; // compile-time
static value_type S_rmod; // runtime
value_type M_value = 0;
static constexpr value_type S_inv(value_type n, value_type m) {
value_type x = 0;
value_type y = 1;
value_type a = n;
value_type b = m;
for (value_type u = y, v = x; a;) {
value_type q = b / a;
std::swap(x -= q*u, u);
std::swap(y -= q*v, v);
std::swap(b -= q*a, a);
}
if ((x %= m) < 0) x += m;
return x;
}
static value_type S_normalize(intmax_t n, value_type m) {
if (n >= m) {
n %= m;
} else if (n < 0) {
if ((n %= m) < 0) n += m;
}
return n;
}
public:
modint() = default;
modint(intmax_t n): M_value(S_normalize(n, get_modulo())) {}
modint& operator =(intmax_t n) {
M_value = S_normalize(n, get_modulo());
return *this;
}
modint& operator +=(modint const& that) {
if ((M_value += that.M_value) >= get_modulo()) M_value -= get_modulo();
return *this;
}
modint& operator -=(modint const& that) {
if ((M_value -= that.M_value) < 0) M_value += get_modulo();
return *this;
}
modint& operator *=(modint const& that) {
intmax_t tmp = M_value;
tmp *= that.M_value;
M_value = tmp % get_modulo();
return *this;
}
modint& operator /=(modint const& that) {
intmax_t tmp = M_value;
tmp *= S_inv(that.M_value, get_modulo());
M_value = tmp % get_modulo();
return *this;
}
modint& operator ++() {
if (++M_value == get_modulo()) M_value = 0;
return *this;
}
modint& operator --() {
if (M_value-- == 0) M_value = get_modulo()-1;
return *this;
}
modint operator ++(int) { modint tmp(*this); ++*this; return tmp; }
modint operator --(int) { modint tmp(*this); --*this; return tmp; }
friend modint operator +(modint lhs, modint const& rhs) { return lhs += rhs; }
friend modint operator -(modint lhs, modint const& rhs) { return lhs -= rhs; }
friend modint operator *(modint lhs, modint const& rhs) { return lhs *= rhs; }
friend modint operator /(modint lhs, modint const& rhs) { return lhs /= rhs; }
modint operator +() const { return *this; }
modint operator -() const {
if (M_value == 0) return *this;
return modint(get_modulo() - M_value);
}
friend bool operator ==(modint const& lhs, modint const& rhs) {
return lhs.M_value == rhs.M_value;
}
friend bool operator !=(modint const& lhs, modint const& rhs) {
return !(lhs == rhs);
}
value_type get() const { return M_value; }
static value_type get_modulo() { return ((S_cmod > 0)? S_cmod: S_rmod); }
template <int M = Modulo, typename Tp = typename std::enable_if<(M <= 0)>::type>
static Tp set_modulo(value_type m) { S_rmod = m; }
};
template <intmax_t N>
constexpr typename modint<N>::value_type modint<N>::S_cmod;
template <intmax_t N>
typename modint<N>::value_type modint<N>::S_rmod;
#line 11 "test/aoj_2444.test.cpp"
constexpr intmax_t mod = 998244353;
using mi = modint<mod>;
int main() {
size_t n, m;
scanf("%zu %zu", &n, &m);
char buf[393216];
scanf("%s", buf);
std::string s = buf;
foldable_deque<rolling_hash_monoid<mi>> dq1, dq2;
std::set<std::pair<intmax_t, intmax_t>> seen;
size_t il = 0, ir = 0;
mi b1 = 80067846, b2 = 365378971;
char c = s[ir++];
dq1.emplace_back(c, b1);
dq2.emplace_back(c, b2);
for (size_t i = 0; i < m; ++i) {
scanf("%s", buf);
std::string q = buf;
if (q == "L++") {
++il;
dq1.pop_front();
dq2.pop_front();
} else if (q == "L--") {
c = s[--il];
dq1.emplace_front(c, b1);
dq2.emplace_front(c, b2);
} else if (q == "R++") {
c = s[ir++];
dq1.emplace_back(c, b1);
dq2.emplace_back(c, b2);
} else if (q == "R--") {
--ir;
dq1.pop_back();
dq2.pop_back();
}
int x1 = dq1.fold().get().get();
int x2 = dq2.fold().get().get();
seen.emplace(x1, x2);
}
printf("%zu\n", seen.size());
}
test/aoj_2444.test.cpp