#1152383 (C++23) No.238 Mr. K's Another Gift

• 問題: No.238 Mr. K's Another Gift
• ユーザー: zeta
• 提出日時: 2026-03-14 06:36:26
• 言語: C++23 (gcc 15.2.0 + boost 1.89.0)
• 結果: AC
• 実行時間: 6 ms / 2,000 ms
• コード長: 14,114 bytes
• コンパイル時間: 2,696 ms
• コンパイル使用メモリ: 274,564 KB
• 実行使用メモリ: 6,384 KB
• 最終ジャッジ日時: 2026-03-14 06:36:40
• 合計ジャッジ時間: 4,715 ms
• ジャッジサーバーID （参考情報）: judge2_0 / judge3_0

ファイルパターン	結果
sample	AC * 3
other	AC * 40

ソースコード

#define YRSD

#include <iostream>
#include <algorithm>
#include <array>
#include <bitset>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <string>
#include <tuple>
#include <bit>
#include <chrono>
#include <functional>
#include <iomanip>
#include <utility>
#include <type_traits>
#include <cassert>
#include <cctype>
#include <cmath>
#include <cstring>
#include <ctime>
#include <limits>
#include <ranges>
#include <concepts>

#define TE template <typename T>
#define TES template <typename T, typename ...S>
#define Z auto
#define ep emplace_back
#define eb emplace
#define fi first
#define se second
#define bg begin
#define ed end
#define all(x) bg(x), ed(x)

#define ov(a, b, c, d, e, ...) e
#define FO1(a) for (int _ = 0; _ < (a); ++_)
#define FO2(i, a) for (int i = 0; i < (a); ++i)
#define FO3(i, a, b) for (int i = (a); i < (b); ++i)
#define FO4(i, a, b, c) for (int i = (a); i < (b); i += (c))
#define FOR(...) ov(__VA_ARGS__, FO4, FO3, FO2, FO1)(__VA_ARGS__)
#define FF1(a) for (int _ = (a) - 1; _ >= 0; --_)
#define FF2(i, a) for (int i = (a) - 1; i >= 0; --i)
#define FF3(i, a, b) for (int i = (b) - 1; i >= (a); --i)
#define FF4(i, a, b, c) for (int i = (b) - 1; i >= (a); i -= (c))
#define FOR_R(...) ov(__VA_ARGS__, FF4, FF3, FF2, FF1)(__VA_ARGS__)
#define FOR_subset(t, s) for (int t = (s); t > -1; t = (t == 0 ? -1 : (t - 1) & s))

#define sort ranges::sort

using namespace std;

TE using vc = vector<T>;
TE using vvc = vc<vc<T>>;
TE using T1 = tuple<T>;
TE using T2 = tuple<T, T>;
TE using T3 = tuple<T, T, T>;
TE using T4 = tuple<T, T, T, T>;
TE using max_heap = priority_queue<T>;
TE using min_heap = priority_queue<T, vc<T>, greater<T>>;
using u8 = unsigned char; using uint = unsigned int; using ll = long long;      using ull = unsigned long long;
using ld = long double;   using i128 = __int128;     using u128 = __uint128_t;  using f128 = __float128;
using u16 = uint16_t;
using PII = pair<int, int>;   using PLL = pair<ll, ll>;

#ifdef YRSD
constexpr bool dbg = 1;
#else
constexpr bool dbg = 0;
#endif

istream &operator>>(istream &I, i128 &x) {
  static string s;
  I >> s;
  int f = s[0] == '-';
  x = 0;
  const int N = (int)s.size();
  FOR(i, f, N) x = x * 10 + s[i] - '0';
  if (f) x = -x;
  return I;
}
ostream &operator<<(ostream &O, i128 x) {
  static string s;
  s.clear();
  bool f = x < 0;
  if (f) x = -x;
  while (x) s += '0' + x % 10, x /= 10;
  if (s.empty()) s += '0';
  if (f) s += '-';
  reverse(all(s));
  return O << s;
}
istream &operator>>(istream &I, f128 &x) {
  static string s;
  I >> s, x = stold(s);
  return I;
}
ostream &operator<<(ostream &O, const f128 x) { return O << ld(x); }
template <typename... S>
istream &operator>>(istream &I, tuple<S...> &t) {
  return apply([&I](Z &...s) { ((I >> s), ...); }, t), I;
}
template <typename T, typename U>
istream &operator>>(istream &I, pair<T, U> &x) {
  return I >> x.fi >> x.se;
}
template <typename T, typename U>
ostream &operator<<(ostream &O, const pair<T, U> &x) {
  return O << x.fi << ' ' << x.se;
}
TE requires requires(T &c) { begin(c); end(c); } and 
                          (not is_same_v<decay_t<T>, string>)
istream &operator>>(istream &I, T &c) {
  for (Z &e : c) I >> e;
  return I;
}
TE requires requires(const T &c) { begin(c); end(c); } and 
  (not is_same_v<decay_t<T>, const char*>) and 
  (not is_same_v<decay_t<T>, string>) and 
  (not is_array_v<remove_reference_t<T>> or 
   not is_same_v<remove_extent_t<remove_reference_t<T>>, char>)
ostream &operator<<(ostream &O, const T &a) {
  if (a.empty()) return O;
  Z i = a.begin();
  O << *i++;
  for (; i != a.end(); ++i) O << ' ' << *i;
  return O;
}
void IN() {}
TE void IN(T &x, Z &...s) { cin >> x, IN(s...); }
void print() { cout << '\n'; }
TES void print(T &&x, S &&...y) {
  cout << x;
  if constexpr (sizeof...(S)) cout << ' ';
  print(forward<S>(y)...);
}
void put() {}
TES void put(T &&x, S &&...y) {
  cout << x;
  put(forward<S>(y)...);
}

#define INT(...)  int    __VA_ARGS__; IN(__VA_ARGS__)
#define UINT(...) uint   __VA_ARGS__; IN(__VA_ARGS__)
#define LL(...)   ll     __VA_ARGS__; IN(__VA_ARGS__)
#define ULL(...)  ull    __VA_ARGS__; IN(__VA_ARGS__)
#define I128(...) i128   __VA_ARGS__; IN(__VA_ARGS__)
#define STR(...)  string __VA_ARGS__; IN(__VA_ARGS__)
#define CH(...)   char   __VA_ARGS__; IN(__VA_ARGS__)
#define REAL(...) re     __VA_ARGS__; IN(__VA_ARGS__)
#define VEC(T, a, n) vc<T> a(n); IN(a)

void YES(bool o = 1) { print(o ? "YES" : "NO"); }
void Yes(bool o = 1) { print(o ? "Yes" : "No"); }
void yes(bool o = 1) { print(o ? "yes" : "no"); }
void NO(bool o = 1) { YES(not o); }
void No(bool o = 1) { Yes(not o); }
void no(bool o = 1) { yes(not o); }
void ALICE(bool o = 1) { print(o ? "ALICE" : "BOB"); }
void Alice(bool o = 1) { print(o ? "Alice" : "Bob"); }
void alice(bool o = 1) { print(o ? "alice" : "bob"); }
void BOB(bool o = 1) { ALICE(not o); }
void Bob(bool o = 1) { Alice(not o); }
void bob(bool o = 1) { alice(not o); }
void POSSIBLE(bool o = 1) { print(o ? "POSSIBLE" : "IMPOSSIBLE"); }
void Possible(bool o = 1) { print(o ? "Possible" : "Impossible"); }
void possible(bool o = 1) { print(o ? "possible" : "impossible"); }
void IMPOSSIBLE(bool o = 1) { POSSIBLE(not o); }
void Impossible(bool o = 1) { Possible(not o); }
void impossible(bool o = 1) { possible(not o); }
void TAK(bool o = 1) { print(o ? "TAK" : "NIE"); }
void NIE(bool o = 1) { TAK(not o); }

#if (__cplusplus >= 202002L)
#include <numbers>
constexpr ld pi = numbers::pi_v<ld>;
#endif
TE constexpr T inf = numeric_limits<T>::max();
template <> constexpr i128 inf<i128> = i128(inf<ll>) * 2'000'000'000'000'000'000;
template <typename T, typename U>
constexpr pair<T, U> inf<pair<T, U>> = {inf<T>, inf<U>};

TE constexpr static inline int pc(T x) { return popcount(make_unsigned_t<T>(x)); }
constexpr static inline ll len(const Z &a) { return a.size(); }

void reverse(Z &a) { reverse(all(a)); }

void unique(Z &a) {
  sort(a);
  a.erase(unique(all(a)), a.end());
}
TE vc<int> inverse(const vc<T> &a) {
  int N = len(a);
  vc<int> b(N, -1);
  FOR(i, N) if (a[i] != -1) b[a[i]] = i;
  return b;
}

Z QMAX(const Z &a) { return *max_element(all(a)); }
Z QMIN(const Z &a) { return *min_element(all(a)); }
TE Z QMAX(T l, T r) { return *max_element(l, r); }
TE Z QMIN(T l, T r) { return *min_element(l, r); }
constexpr bool chmax(Z &a, const Z &b) { return (a < b ? a = b, 1 : 0); }
constexpr bool chmin(Z &a, const Z &b) { return (a > b ? a = b, 1 : 0); }

vc<int> argsort(const Z &a) {
  vc<int> I(len(a));
  iota(all(I), 0);
  sort(I, [&](int i, int k) { return a[i] < a[k] or (a[i] == a[k] and i < k); });
  return I;
}
TE vc<T> rearrange(const vc<T> &a, const vc<int> &I) {
  int N = len(I);
  vc<T> b(N);
  FOR(i, N) b[i] = a[I[i]];
  return b;
}
template <int of = 1, typename T> 
vc<T> pre_sum(const vc<T> &a) {
  int N = len(a);
  vc<T> c(N + 1);
  FOR(i, N) c[i + 1] = c[i] + a[i];
  if (of == 0) c.erase(c.begin());
  return c;
}

TE constexpr static int topbit(T x) {
  if (x == 0) return - 1;
  if constexpr (sizeof(T) <= 4) return 31 - __builtin_clz(x);
  else return 63 - __builtin_clzll(x);
}
TE constexpr static int lowbit(T x) {
  if (x == 0) return -1;
  if constexpr (sizeof(T) <= 4) return __builtin_ctz(x);
  else return __builtin_ctzll(x);
}

TE constexpr T floor(T x, T y) { return x / y - (x % y and (x ^ y) < 0); }
TE constexpr T ceil(T x, T y) { return floor(x + y - 1, y); }
TE constexpr T bmod(T x, T y) { return x - floor(x, y) * y; }
TE constexpr pair<T, T> divmod(T x, T y) {
  T q = floor(x, y);
  return pair{q, x - q * y};
}
template <typename T = ll>
T SUM(const Z &v) {
  return accumulate(all(v), T(0));
}
int lb(const Z &a, Z x) { return lower_bound(all(a), x) - a.begin(); }
TE int lb(T l, T r, Z x) { return lower_bound(l, r, x) - l; }
int ub(const Z &a, Z x) { return upper_bound(all(a), x) - a.begin(); }
TE int ub(T l, T r, Z x) { return upper_bound(l, r, x) - l; }

template <bool ck = 1>
ll bina(Z f, ll l, ll r) {
  if constexpr (ck) assert(f(l));
  while (abs(l - r) > 1) {
    ll x = (r + l) >> 1;
    (f(x) ? l : r) = x;
  }
  return l;
}
TE T bina_real(Z f, T l, T r, int c = 100) {
  while (c--) {
    T x = (l + r) / 2;
    (f(x) ? l : r) = x;
  }
  return (l + r) / 2;
}

Z pop(Z &s) {
  if constexpr (requires { s.pop_back(); }) {
    Z x = s.back();
    return s.pop_back(), x;
  } else if constexpr (requires { s.top(); }) {
    Z x = s.top();
    return s.pop(), x;
  } else {
    Z x = s.front();
    return s.pop(), x;
  }
}
void setp(int x) { cout << fixed << setprecision(x); }

TE inline void sh(vc<T> &a, int N, T b = {}) {
  a.resize(N, b);
}
#ifdef YRSD
void DBG() { cerr << "]" << endl; }
TES void DBG(T &&x, S &&...y) {
  cerr << x;
  if constexpr (sizeof...(S)) cerr << ", ";
  DBG(forward<S>(y)...);
}
#define debug(...) cerr << "[" << __LINE__ << "]: [" #__VA_ARGS__ "] = [", DBG(__VA_ARGS__)
void ERR() { cerr << endl; }
TES void ERR(T &&x, S &&...y) {
  cerr << x;
  if constexpr (sizeof...(S)) cerr << ", ";
  ERR(forward<S>(y)...);
}
#define err(...) cerr << "[" << __LINE__ << "]: ", ERR(__VA_ARGS__)
#else
#define debug(...) void(0721)
#define err(...)   void(0721)
#endif

#define c constexpr
struct m61 {
  using T = m61;
  static c ull m = (1ull << 61) - 1;
  ull x;

  static c ull get_mod() { return m; }

  c m61() : x(0ull) {}
  c m61(uint x) : x(x) {}
  c m61(ull x) : x(x % m) {}
  c m61(int x) : x((x < 0) ? (x + ll(m)) : x) {}
  c m61(ll x) : x(((x %= ll(m)) < 0) ? (x + ll(m)) : x) {}

  c T &operator+=(const T &a) {
    return x = ((x += a.x) >= m) ? (x - m) : x, *this;
  }

  c T &operator-=(const T &a) {
    return x = ((x -= a.x) >= m) ? (x + m) : x, *this;
  }

  c T &operator*=(const T &a) {
    u128 y = u128(x) * a.x;
    x = (y >> 61) + (y & m);
    x = (x >= m) ? (x - m) : x;
    return *this;
  }

  c T &operator/=(const T &a) { return *this *= a.inv(); }

  c T operator+(const T &p) const { return T(*this) += p; }
  c T operator-(const T &p) const { return T(*this) -= p; }
  c T operator*(const T &p) const { return T(*this) *= p; }
  c T operator/(const T &p) const { return T(*this) /= p; }

  c T operator-() const { return T(x ? m - x : 0ull); }

  c bool operator<(const T &p) const { return x < p.x; }
  c bool operator==(const T &p) const { return x == p.x; }
  c bool operator!=(const T &p) const { return x != p.x; }

  friend ostream &operator<<(ostream &os, T p) { return os << p.x; }

  c ull val() const { return x; }

  c T inv() const {
    ll a = x, b = m, u = 1, v = 0, t;
    while (b > 0) {
      t = a / b;
      swap(a -= t * b, b), swap(u -= t * v, v);
    }
    return T(u);
  }

  c T pow(ll k) const {
    assert(k >= 0);
    T r(1), a(x);
    for (; k; k >>= 1, a *= a) {
      if (k & 1) r *= a;
    }
    return r;
  }
};
#undef c

struct const_pr {
  static constexpr ll pw(ll a, ll n, ll p) {
    ll s = 1;
    for (; n; n >>= 1, a = u128(a) * a % p) {
      if (n & 1) s = u128(s) * a % p;
    }
    return s;
  }
  static constexpr bool ck(ll p) {
    if (p == 1) return 0;
    ll d = lowbit(p - 1), s = (p - 1) >> d;
    for (ll a : {2, 3, 5, 7, 11, 13, 82, 373}) {
      if (a % p == 0) continue;
      ll x = pw(a, s, p), y = 0;
      for (int i = 0; i < d; ++i, x = y) {
        y = (u128)x * x % p;
        if (y == 1 && x != 1 && x != p - 1) return 0;
      }
      if (x != 1) return 0;
    }
    return 1;
  }
  constexpr ll gen(ll l, ll r) {
    ull x = 131;
    for (char c : __TIME__ __TIMESTAMP__) {
      x += c;
      x ^= x << 13;
      x ^= x >> 7;
      x ^= x << 17;
    }
    while (1) {
      x ^= x << 13, x ^= x >> 7, x ^= x << 17;
      ll s = l + x % (r - l);
      if (ck(s)) return s;
    }
  }
};

struct hsh_base {
  using T = m61;
  static constexpr T b = const_pr{}.gen(3, T::get_mod());
  int sz = 1;
  vc<T> a{1};

  void ext(int N) {
    while (sz < N) sz <<= 1;
    N = len(a);
    sh(a, sz);
    FOR(i, N, sz) a[i] = a[i - 1] * b;
  }

  T operator[](int i) {
    if (i >= sz) ext(i + 1);
    return a[i];
  }
} hsh_pw;

#define pw hsh_pw

struct hsh {
  using T = m61;
  using X = pair<int, T>;
  static constexpr T b = pw.b;

  int N;
  vc<T> a;
  hsh() {}
  hsh(const Z &s) { build(s); }

  void build(const Z &s) {
    N = len(s);
    a.assign(N + 1, T());
    FOR(i, N) a[i + 1] = a[i] * b + T(s[i]) + 1;
  }

  ll size() const { return N; }

  X get(int l, int r) const {
    assert(l <= r and r <= N);
    int sz = r - l;
    return {sz, a[r] - a[l] * pw[sz]};
  }

  X get_all() const { return {N, a[N]}; }

  static X merge(X a, X b) {
    return {a.fi + b.fi, a.se * pw[b.fi] + b.se};
  }

  static int lcp(const hsh &a, int l, int r, const hsh &b, int ll, int rr) {
    int sz = min(r - l, rr - ll);
    int L = 0, R = sz + 1;
    while (R - L > 1) {
      int m = (R + L) >> 1;
      if (a.get(l, l + m) == b.get(ll, ll + m)) {
        L = m;
      } else {
        R = m;
      }
    }
    return L;
  }
};
#undef pw

void Yorisou() {
  STR(s);
  string rs = s;
  reverse(rs);
  hsh hs(s + rs);
  int N = len(s);
  Z pa = [&](int l, int r) {
    return hs.get(l, r) == hs.get(N + N - r, N + N - l);
  };

  FOR(lsz, N + 1) {
    int rsz = N - lsz, l = 0, r = lsz, ll = r, rr = N;
    if (lsz == rsz) {
      if (hs.get(l, r) == hs.get(N + N - rr, N + N - ll)) {
        return print(s.substr(l, lsz) + 'a' + s.substr(ll));
      }
    } else if (lsz < rsz) {
      if (hs.get(l, r) == hs.get(N + N - rr, N + N - (rr - lsz))) {
        rr -= lsz;
        char c = s[--rr];
        if (pa(ll, rr)) {
          return print(s.substr(l, lsz) + c + s.substr(ll));
        }
      }
    } else {
      if (hs.get(l, l + rsz) == hs.get(N + N - rr, N + N - ll)) {
        l += rsz;
        char c = s[l++];
        if (pa(l, r)) {
          return print(s.substr(0, lsz) + c + s.substr(lsz));
        }
      }
    }
  }
  print("NA");
}
constexpr int tests = 0, fl = 0, DB = 10;
int main() {
  cin.tie(0)->sync_with_stdio(0);
  int T = 1;
  if (fl) cerr.tie(0);
  if (tests and not fl) IN(T);
  for (int i = 0; i < T or fl; ++i) {
    Yorisou();
    if (fl and i % DB == 0) cerr << "Case: " << i << '\n';
  }
  return 0;
}