結果
| 問題 | No.1951 消えたAGCT(2) |
| ユーザー |
 suisen
|
| 提出日時 | 2022-05-20 23:14:47 |
| 言語 | C++17 (gcc 12.3.0 + boost 1.83.0) |
| 結果 |
AC
|
| 実行時間 | 753 ms / 3,000 ms |
| コード長 | 23,805 bytes |
| コンパイル時間 | 2,722 ms |
| コンパイル使用メモリ | 228,628 KB |
| 実行使用メモリ | 331,904 KB |
| 最終ジャッジ日時 | 2024-09-20 09:37:57 |
| 合計ジャッジ時間 | 14,894 ms |
|
ジャッジサーバーID （参考情報） |
judge5 / judge1 |
（要ログイン）
テストケース
テストケース表示| 入力 | 結果 | 実行時間 実行使用メモリ |
|---|---|---|
| testcase_00 | AC | 225 ms
331,304 KB |
| testcase_01 | AC | 229 ms
331,308 KB |
| testcase_02 | AC | 231 ms
331,320 KB |
| testcase_03 | AC | 231 ms
331,372 KB |
| testcase_04 | AC | 228 ms
331,308 KB |
| testcase_05 | AC | 226 ms
331,352 KB |
| testcase_06 | AC | 229 ms
331,320 KB |
| testcase_07 | AC | 230 ms
331,336 KB |
| testcase_08 | AC | 242 ms
331,680 KB |
| testcase_09 | AC | 246 ms
331,720 KB |
| testcase_10 | AC | 241 ms
331,904 KB |
| testcase_11 | AC | 243 ms
331,904 KB |
| testcase_12 | AC | 239 ms
331,636 KB |
| testcase_13 | AC | 241 ms
331,496 KB |
| testcase_14 | AC | 707 ms
331,828 KB |
| testcase_15 | AC | 614 ms
331,776 KB |
| testcase_16 | AC | 656 ms
331,776 KB |
| testcase_17 | AC | 753 ms
331,800 KB |
| testcase_18 | AC | 736 ms
331,744 KB |
| testcase_19 | AC | 733 ms
331,816 KB |
| testcase_20 | AC | 736 ms
331,852 KB |
| testcase_21 | AC | 238 ms
331,876 KB |
| testcase_22 | AC | 238 ms
331,744 KB |
| testcase_23 | AC | 242 ms
331,888 KB |
| testcase_24 | AC | 242 ms
331,892 KB |
| testcase_25 | AC | 242 ms
331,776 KB |
| testcase_26 | AC | 747 ms
331,848 KB |
| testcase_27 | AC | 742 ms
331,840 KB |
ソースコード
#include <bits/stdc++.h>
#include <limits>
#include <type_traits>
namespace suisen {
// ! utility
template <typename ...Types>
using constraints_t = std::enable_if_t<std::conjunction_v<Types...>, std::nullptr_t>;
template <bool cond_v, typename Then, typename OrElse>
constexpr decltype(auto) constexpr_if(Then&& then, OrElse&& or_else) {
if constexpr (cond_v) {
return std::forward<Then>(then);
} else {
return std::forward<OrElse>(or_else);
}
}
// ! function
template <typename ReturnType, typename Callable, typename ...Args>
using is_same_as_invoke_result = std::is_same<std::invoke_result_t<Callable, Args...>, ReturnType>;
template <typename F, typename T>
using is_uni_op = is_same_as_invoke_result<T, F, T>;
template <typename F, typename T>
using is_bin_op = is_same_as_invoke_result<T, F, T, T>;
template <typename Comparator, typename T>
using is_comparator = std::is_same<std::invoke_result_t<Comparator, T, T>, bool>;
// ! integral
template <typename T, typename = constraints_t<std::is_integral<T>>>
constexpr int bit_num = std::numeric_limits<std::make_unsigned_t<T>>::digits;
template <typename T, unsigned int n>
struct is_nbit { static constexpr bool value = bit_num<T> == n; };
template <typename T, unsigned int n>
static constexpr bool is_nbit_v = is_nbit<T, n>::value;
// ?
template <typename T>
struct safely_multipliable {};
template <>
struct safely_multipliable<int> { using type = long long; };
template <>
struct safely_multipliable<long long> { using type = __int128_t; };
template <>
struct safely_multipliable<unsigned int> { using type = unsigned long long; };
template <>
struct safely_multipliable<unsigned long int> { using type = __uint128_t; };
template <>
struct safely_multipliable<unsigned long long> { using type = __uint128_t; };
template <>
struct safely_multipliable<float> { using type = float; };
template <>
struct safely_multipliable<double> { using type = double; };
template <>
struct safely_multipliable<long double> { using type = long double; };
template <typename T>
using safely_multipliable_t = typename safely_multipliable<T>::type;
} // namespace suisen
// ! type aliases
using i128 = __int128_t;
using u128 = __uint128_t;
template <typename T>
using pq_greater = std::priority_queue<T, std::vector<T>, std::greater<T>>;
template <typename T, typename U>
using umap = std::unordered_map<T, U>;
// ! macros (capital: internal macro)
#define OVERLOAD2(_1,_2,name,...) name
#define OVERLOAD3(_1,_2,_3,name,...) name
#define OVERLOAD4(_1,_2,_3,_4,name,...) name
#define REP4(i,l,r,s) for(std::remove_reference_t<std::remove_const_t<decltype(r)>>i=(l);i<(r);i+=(s))
#define REP3(i,l,r) REP4(i,l,r,1)
#define REP2(i,n) REP3(i,0,n)
#define REPINF3(i,l,s) for(std::remove_reference_t<std::remove_const_t<decltype(l)>>i=(l);;i+=(s))
#define REPINF2(i,l) REPINF3(i,l,1)
#define REPINF1(i) REPINF2(i,0)
#define RREP4(i,l,r,s) for(std::remove_reference_t<std::remove_const_t<decltype(r)>>i=(l)+fld((r)-(l)-1,s)*(s);i>=(l);i-=(s))
#define RREP3(i,l,r) RREP4(i,l,r,1)
#define RREP2(i,n) RREP3(i,0,n)
#define rep(...) OVERLOAD4(__VA_ARGS__, REP4 , REP3 , REP2 )(__VA_ARGS__)
#define rrep(...) OVERLOAD4(__VA_ARGS__, RREP4 , RREP3 , RREP2 )(__VA_ARGS__)
#define repinf(...) OVERLOAD3(__VA_ARGS__, REPINF3, REPINF2, REPINF1)(__VA_ARGS__)
#define CAT_I(a, b) a##b
#define CAT(a, b) CAT_I(a, b)
#define UNIQVAR(tag) CAT(tag, __LINE__)
#define loop(n) for (std::remove_reference_t<std::remove_const_t<decltype(n)>> UNIQVAR(loop_variable) = n; UNIQVAR(loop_variable) --> 0;)
#define all(iterable) std::begin(iterable), std::end(iterable)
#define input(type, ...) type __VA_ARGS__; read(__VA_ARGS__)
#ifdef LOCAL
# define debug(...) debug_internal(#__VA_ARGS__, __VA_ARGS__)
template <class T, class... Args>
void debug_internal(const char* s, T&& first, Args&&... args) {
constexpr const char* prefix = "[\033[32mDEBUG\033[m] ";
constexpr const char* open_brakets = sizeof...(args) == 0 ? "" : "(";
constexpr const char* close_brakets = sizeof...(args) == 0 ? "" : ")";
std::cerr << prefix << open_brakets << s << close_brakets << ": " << open_brakets << std::forward<T>(first);
((std::cerr << ", " << std::forward<Args>(args)), ...);
std::cerr << close_brakets << "\n";
}
#else
# define debug(...) void(0)
#endif
// ! I/O utilities
// pair
template <typename T, typename U>
std::ostream& operator<<(std::ostream& out, const std::pair<T, U> &a) {
return out << a.first << ' ' << a.second;
}
// tuple
template <unsigned int N = 0, typename ...Args>
std::ostream& operator<<(std::ostream& out, const std::tuple<Args...> &a) {
if constexpr (N >= std::tuple_size_v<std::tuple<Args...>>) {
return out;
} else {
out << std::get<N>(a);
if constexpr (N + 1 < std::tuple_size_v<std::tuple<Args...>>) {
out << ' ';
}
return operator<<<N + 1>(out, a);
}
}
// vector
template <typename T>
std::ostream& operator<<(std::ostream& out, const std::vector<T> &a) {
for (auto it = a.begin(); it != a.end();) {
out << *it;
if (++it != a.end()) out << ' ';
}
return out;
}
// array
template <typename T, size_t N>
std::ostream& operator<<(std::ostream& out, const std::array<T, N> &a) {
for (auto it = a.begin(); it != a.end();) {
out << *it;
if (++it != a.end()) out << ' ';
}
return out;
}
inline void print() { std::cout << '\n'; }
template <typename Head, typename... Tail>
inline void print(const Head &head, const Tail &...tails) {
std::cout << head;
if (sizeof...(tails)) std::cout << ' ';
print(tails...);
}
template <typename Iterable>
auto print_all(const Iterable& v, std::string sep = " ", std::string end = "\n") -> decltype(std::cout << *v.begin(), void()) {
for (auto it = v.begin(); it != v.end();) {
std::cout << *it;
if (++it != v.end()) std::cout << sep;
}
std::cout << end;
}
// pair
template <typename T, typename U>
std::istream& operator>>(std::istream& in, std::pair<T, U> &a) {
return in >> a.first >> a.second;
}
// tuple
template <unsigned int N = 0, typename ...Args>
std::istream& operator>>(std::istream& in, std::tuple<Args...> &a) {
if constexpr (N >= std::tuple_size_v<std::tuple<Args...>>) {
return in;
} else {
return operator>><N + 1>(in >> std::get<N>(a), a);
}
}
// vector
template <typename T>
std::istream& operator>>(std::istream& in, std::vector<T> &a) {
for (auto it = a.begin(); it != a.end(); ++it) in >> *it;
return in;
}
// array
template <typename T, size_t N>
std::istream& operator>>(std::istream& in, std::array<T, N> &a) {
for (auto it = a.begin(); it != a.end(); ++it) in >> *it;
return in;
}
template <typename ...Args>
void read(Args &...args) {
( std::cin >> ... >> args );
}
// ! integral utilities
// Returns pow(-1, n)
template <typename T>
constexpr inline int pow_m1(T n) {
return -(n & 1) | 1;
}
// Returns pow(-1, n)
template <>
constexpr inline int pow_m1<bool>(bool n) {
return -int(n) | 1;
}
// Returns floor(x / y)
template <typename T>
constexpr inline T fld(const T x, const T y) {
return (x ^ y) >= 0 ? x / y : (x - (y + pow_m1(y >= 0))) / y;
}
template <typename T>
constexpr inline T cld(const T x, const T y) {
return (x ^ y) <= 0 ? x / y : (x + (y + pow_m1(y >= 0))) / y;
}
template <typename T, suisen::constraints_t<suisen::is_nbit<T, 16>> = nullptr>
constexpr inline int popcount(const T x) { return __builtin_popcount(x); }
template <typename T, suisen::constraints_t<suisen::is_nbit<T, 32>> = nullptr>
constexpr inline int popcount(const T x) { return __builtin_popcount(x); }
template <typename T, suisen::constraints_t<suisen::is_nbit<T, 64>> = nullptr>
constexpr inline int popcount(const T x) { return __builtin_popcountll(x); }
template <typename T, suisen::constraints_t<suisen::is_nbit<T, 16>> = nullptr>
constexpr inline int count_lz(const T x) { return x ? __builtin_clz(x) : suisen::bit_num<T>; }
template <typename T, suisen::constraints_t<suisen::is_nbit<T, 32>> = nullptr>
constexpr inline int count_lz(const T x) { return x ? __builtin_clz(x) : suisen::bit_num<T>; }
template <typename T, suisen::constraints_t<suisen::is_nbit<T, 64>> = nullptr>
constexpr inline int count_lz(const T x) { return x ? __builtin_clzll(x) : suisen::bit_num<T>; }
template <typename T, suisen::constraints_t<suisen::is_nbit<T, 16>> = nullptr>
constexpr inline int count_tz(const T x) { return x ? __builtin_ctz(x) : suisen::bit_num<T>; }
template <typename T, suisen::constraints_t<suisen::is_nbit<T, 32>> = nullptr>
constexpr inline int count_tz(const T x) { return x ? __builtin_ctz(x) : suisen::bit_num<T>; }
template <typename T, suisen::constraints_t<suisen::is_nbit<T, 64>> = nullptr>
constexpr inline int count_tz(const T x) { return x ? __builtin_ctzll(x) : suisen::bit_num<T>; }
template <typename T>
constexpr inline int floor_log2(const T x) { return suisen::bit_num<T> - 1 - count_lz(x); }
template <typename T>
constexpr inline int ceil_log2(const T x) { return floor_log2(x) + ((x & -x) != x); }
template <typename T>
constexpr inline int kth_bit(const T x, const unsigned int k) { return (x >> k) & 1; }
template <typename T>
constexpr inline int parity(const T x) { return popcount(x) & 1; }
struct all_subset {
struct all_subset_iter {
const int s; int t;
constexpr all_subset_iter(int s) : s(s), t(s + 1) {}
constexpr auto operator*() const { return t; }
constexpr auto operator++() {}
constexpr auto operator!=(std::nullptr_t) { return t ? (--t &= s, true) : false; }
};
int s;
constexpr all_subset(int s) : s(s) {}
constexpr auto begin() { return all_subset_iter(s); }
constexpr auto end() { return nullptr; }
};
// ! container
template <typename T, typename Comparator, suisen::constraints_t<suisen::is_comparator<Comparator, T>> = nullptr>
auto priqueue_comp(const Comparator comparator) {
return std::priority_queue<T, std::vector<T>, Comparator>(comparator);
}
template <typename Iterable>
auto isize(const Iterable &iterable) -> decltype(int(iterable.size())) {
return iterable.size();
}
template <typename T, typename Gen, suisen::constraints_t<suisen::is_same_as_invoke_result<T, Gen, int>> = nullptr>
auto generate_vector(int n, Gen generator) {
std::vector<T> v(n);
for (int i = 0; i < n; ++i) v[i] = generator(i);
return v;
}
template <typename T>
auto generate_range_vector(T l, T r) {
return generate_vector(r - l, [l](int i) { return l + i; });
}
template <typename T>
auto generate_range_vector(T n) {
return generate_range_vector(0, n);
}
template <typename T>
void sort_unique_erase(std::vector<T> &a) {
std::sort(a.begin(), a.end());
a.erase(std::unique(a.begin(), a.end()), a.end());
}
template <typename InputIterator, typename BiConsumer>
auto foreach_adjacent_values(InputIterator first, InputIterator last, BiConsumer f) -> decltype(f(*first++, *last), void()) {
if (first != last) for (auto itr = first, itl = itr++; itr != last; itl = itr++) f(*itl, *itr);
}
template <typename Container, typename BiConsumer>
auto foreach_adjacent_values(Container c, BiConsumer f) -> decltype(c.begin(), c.end(), void()){
foreach_adjacent_values(c.begin(), c.end(), f);
}
// ! other utilities
// x <- min(x, y). returns true iff `x` has chenged.
template <typename T>
inline bool chmin(T &x, const T &y) {
if (y >= x) return false;
x = y;
return true;
}
// x <- max(x, y). returns true iff `x` has chenged.
template <typename T>
inline bool chmax(T &x, const T &y) {
if (y <= x) return false;
x = y;
return true;
}
namespace suisen {}
using namespace suisen;
using namespace std;
struct io_setup {
io_setup(int precision = 20) {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
std::cout << std::fixed << std::setprecision(precision);
}
} io_setup_ {};
// ! code from here
#include <cassert>
#include <sstream>
#include <string>
#include <tuple>
#include <deque>
#include <vector>
namespace suisen {
template <typename T, bool auto_extend = false>
struct ObjectPool {
using value_type = T;
using value_pointer_type = T*;
template <typename U>
using container_type = std::conditional_t<auto_extend, std::deque<U>, std::vector<U>>;
container_type<value_type> pool;
container_type<value_pointer_type> stock;
decltype(stock.begin()) it;
ObjectPool() : ObjectPool(0) {}
ObjectPool(int siz) : pool(siz), stock(siz) {
clear();
}
int capacity() const { return pool.size(); }
int size() const { return it - stock.begin(); }
value_pointer_type alloc() {
if constexpr (auto_extend) ensure();
return *it++;
}
void free(value_pointer_type t) {
*--it = t;
}
void clear() {
int siz = pool.size();
it = stock.begin();
for (int i = 0; i < siz; i++) stock[i] = &pool[i];
}
void ensure() {
if (it != stock.end()) return;
int siz = stock.size();
for (int i = siz; i <= siz * 2; ++i) {
stock.push_back(&pool.emplace_back());
}
it = stock.begin() + siz;
}
};
} // namespace suisen
namespace suisen::bbst::internal {
template <typename T, typename Derived>
struct RedBlackTreeNodeBase {
enum RedBlackTreeNodeColor { RED, BLACK };
using base_type = void;
using size_type = int;
using value_type = T;
using node_type = Derived;
using tree_type = node_type*;
using color_type = RedBlackTreeNodeColor;
RedBlackTreeNodeBase() = default;
static inline ObjectPool<node_type> pool{};
static void init_pool(int siz) { pool = ObjectPool<node_type>(siz); }
static int node_num() { return pool.size(); }
static tree_type empty_tree() { return nullptr; }
static size_type size(tree_type node) { return node ? node->_siz : 0; }
static bool empty(tree_type node) { return not node; }
template <bool force_black_root = true>
static tree_type merge(tree_type l, tree_type r) {
if (not l) return r;
if (not r) return l;
tree_type res = nullptr;
if (size_type hl = height(l), hr = height(r); hl > hr) {
l = node_type::push(l);
tree_type c = l->_ch[1] = merge<false>(l->_ch[1], r);
if (l->_col == BLACK and c->_col == RED and color(c->_ch[1]) == RED) {
std::swap(l->_col, c->_col);
if (std::exchange(l->_ch[0]->_col, BLACK) == BLACK) return rotate(l, 1);
}
res = node_type::update(l);
} else if (hr > hl) {
r = node_type::push(r);
tree_type c = r->_ch[0] = merge<false>(l, r->_ch[0]);
if (r->_col == BLACK and c->_col == RED and color(c->_ch[0]) == RED) {
std::swap(r->_col, c->_col);
if (std::exchange(r->_ch[1]->_col, BLACK) == BLACK) return rotate(r, 0);
}
res = node_type::update(r);
} else {
res = create_branch(l, r);
}
if constexpr (force_black_root) res->_col = BLACK;
return res;
}
static std::pair<tree_type, tree_type> split(tree_type node, size_type k) {
if (not node) return { nullptr, nullptr };
node = node_type::push(node);
if (k == 0) return { nullptr, node };
if (k == size(node)) return { node, nullptr };
tree_type l = std::exchange(node->_ch[0], nullptr);
tree_type r = std::exchange(node->_ch[1], nullptr);
free_node(node);
if (color(l) == RED) l->_col = BLACK;
if (color(r) == RED) r->_col = BLACK;
size_type szl = size(l);
tree_type m;
if (k < szl) {
std::tie(l, m) = split(l, k);
return { l, merge(m, r) };
}
if (k > szl) {
std::tie(m, r) = split(r, k - szl);
return { merge(l, m), r };
}
return { l, r };
}
static std::tuple<tree_type, tree_type, tree_type> split_range(tree_type node, size_type l, size_type r) {
auto [tlm, tr] = split(node, r);
auto [tl, tm] = split(tlm, l);
return { tl, tm, tr };
}
static tree_type insert(tree_type node, size_type k, const value_type& val) {
auto [tl, tr] = split(node, k);
return merge(merge(tl, create_leaf(val)), tr);
}
static tree_type push_front(tree_type node, const value_type &val) { return insert(node, 0, val); }
static tree_type push_back(tree_type node, const value_type &val) { return insert(node, size(node), val); }
static std::pair<tree_type, value_type> erase(tree_type node, size_type k) {
auto [tl, tm, tr] = split_range(node, k, k + 1);
value_type erased_value = tm->_val;
free_node(tm);
return { merge(tl, tr) , erased_value };
}
static std::pair<tree_type, value_type> pop_front(tree_type node) { return erase(node, 0); }
static std::pair<tree_type, value_type> pop_back(tree_type node) { return erase(node, size(node) - 1); }
template <typename U>
static tree_type build(const std::vector<U>& a, int l, int r) {
if (r - l == 1) return create_leaf(a[l]);
int m = (l + r) >> 1;
return merge(build(a, l, m), build(a, m, r));
}
template <typename U>
static tree_type build(const std::vector<U>& a) {
return a.empty() ? empty_tree() : build(a, 0, a.size());
}
template <typename OutputIterator>
static void dump(tree_type node, OutputIterator it) {
if (empty(node)) return;
auto dfs = [&](auto dfs, tree_type cur) -> void {
if (cur->is_leaf()) {
*it++ = cur->_val;
return;
}
dfs(dfs, cur->_ch[0]);
dfs(dfs, cur->_ch[1]);
};
dfs(dfs, node);
}
// Don't use on persistent tree.
static void free(tree_type node) {
auto dfs = [&](auto dfs, tree_type cur) -> void {
if (not cur) return;
dfs(dfs, cur->_ch[0]);
dfs(dfs, cur->_ch[1]);
free_node(cur);
};
dfs(dfs, node);
}
template <typename ToStr>
static std::string to_string(tree_type node, ToStr f) {
std::vector<value_type> dat;
node_type::dump(node, std::back_inserter(dat));
std::ostringstream res;
int siz = dat.size();
res << '[';
for (int i = 0; i < siz; ++i) {
res << f(dat[i]);
if (i != siz - 1) res << ", ";
}
res << ']';
return res.str();
}
static std::string to_string(tree_type node) {
return to_string(node, [](const auto &e) { return e; });
}
static void check_rbtree_properties(tree_type node) {
assert(color(node) == BLACK);
auto dfs = [&](auto dfs, tree_type cur) -> int {
if (not cur) return 0;
if (cur->_col == RED) {
assert(color(cur->_ch[0]) == BLACK);
assert(color(cur->_ch[1]) == BLACK);
}
int bl = dfs(dfs, cur->_ch[0]);
int br = dfs(dfs, cur->_ch[1]);
assert(bl == br);
return bl + (cur->_col == BLACK);
};
dfs(dfs, node);
}
protected:
color_type _col;
tree_type _ch[2]{ nullptr, nullptr };
value_type _val;
size_type _siz, _lev;
RedBlackTreeNodeBase(const value_type& val) : _col(BLACK), _val(val), _siz(1), _lev(0) {}
RedBlackTreeNodeBase(tree_type l, tree_type r) : _col(RED), _ch{ l, r }, _siz(l->_siz + r->_siz), _lev(l->_lev + (l->_col == BLACK)) {}
static void clear_pool() { pool.clear(); }
static int pool_capacity() { return pool.capacity(); }
static color_type color(tree_type node) { return node ? node->_col : BLACK; }
static size_type height(tree_type node) { return node ? node->_lev : 0; }
bool is_leaf() const { return not (_ch[0] or _ch[1]); }
static tree_type clone(tree_type node) {
return node;
}
static tree_type update(tree_type node) {
node->_siz = node->is_leaf() ? 1 : size(node->_ch[0]) + size(node->_ch[1]);
node->_lev = node->_ch[0] ? height(node->_ch[0]) + (node->_ch[0]->_col == BLACK) : 0;
return node;
}
static tree_type push(tree_type node) {
return node;
}
static tree_type rotate(tree_type node, int index) {
node = node_type::push(node);
tree_type ch_node = node_type::push(node->_ch[index]);
node->_ch[index] = std::exchange(ch_node->_ch[index ^ 1], node);
return node_type::update(node), node_type::update(ch_node);
}
static tree_type create_leaf(const value_type& val = value_type{}) {
return &(*pool.alloc() = node_type(val));
}
static tree_type create_branch(tree_type l, tree_type r) {
return node_type::update(&(*pool.alloc() = node_type(l, r)));
}
static void free_node(tree_type node) {
if (node) pool.free(node);
}
};
} // namespace suisen
namespace suisen::bbst {
template <typename T, template <typename, typename> typename BaseNode = internal::RedBlackTreeNodeBase>
struct RedBlackTreeNode : public BaseNode<T, RedBlackTreeNode<T, BaseNode>> {
using base_type = BaseNode<T, RedBlackTreeNode<T, BaseNode>>;
using node_type = typename base_type::node_type;
using tree_type = typename base_type::tree_type;
using size_type = typename base_type::size_type;
using value_type = typename base_type::value_type;
friend base_type;
friend typename base_type::base_type;
RedBlackTreeNode() = default;
private:
RedBlackTreeNode(const value_type& val) : base_type(val) {}
RedBlackTreeNode(tree_type l, tree_type r) : base_type(l, r) {}
};
}
using Node = bbst::RedBlackTreeNode<char>;
using Tree = Node::tree_type;
constexpr int A = 'A' - 'A';
constexpr int G = 'G' - 'A';
constexpr int C = 'C' - 'A';
constexpr int T = 'T' - 'A';
int main() {
Node::init_pool(7000000);
input(int, n);
vector<char> s(n);
read(s);
auto seq = Node::build(s);
array<int, 26> cnt{};
for (char c : s) {
++cnt[c - 'A'];
}
int offset = 0;
auto get_index = [&](int ch) {
int x = (ch - offset) % 26;
if (x < 0) x += 26;
return x;
};
int ans = 0;
for (;; ++ans) {
int num = cnt[get_index(A)] + cnt[get_index(G)] + cnt[get_index(C)] + cnt[get_index(T)];
if (num == 0) break;
char c;
tie(seq, c) = Node::erase(seq, num - 1);
int ch = (offset + (c - 'A')) % 26;
int c2 = --cnt[get_index(ch)];
offset += c2;
offset %= 26;
}
print(ans);
return 0;
}