結果

問題 No.3096 Snake Path
ユーザー 👑 hos.lyric
提出日時 2025-04-06 16:20:37
言語 D
(dmd 2.109.1)
結果
AC  
実行時間 114 ms / 2,000 ms
コード長 4,450 bytes
コンパイル時間 3,868 ms
コンパイル使用メモリ 141,780 KB
実行使用メモリ 7,844 KB
最終ジャッジ日時 2025-04-06 16:20:56
合計ジャッジ時間 6,078 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge2
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ファイルパターン 結果
other AC * 35
権限があれば一括ダウンロードができます

ソースコード

diff # 

import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }

string COLOR(string s = "") { return "\x1b[" ~ s ~ "m"; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }

struct ModInt(uint M_) {
  import std.conv : to;
  alias M = M_;
  uint x;
  this(ModInt a) { x = a.x; }
  this(uint x_) { x = x_ % M; }
  this(ulong x_) { x = cast(uint)(x_ % M); }
  this(int x_) { x = ((x_ %= cast(int)(M)) < 0) ? (x_ + cast(int)(M)) : x_; }
  this(long x_) { x = cast(uint)(((x_ %= cast(long)(M)) < 0) ? (x_ + cast(long)(M)) : x_); }
  ref ModInt opAssign(T)(inout(T) a) if (is(T == uint) || is(T == ulong) || is(T == int) || is(T == long)) { return this = ModInt(a); }
  ref ModInt opOpAssign(string op, T)(T a) {
    static if (is(T == ModInt)) {
      static if (op == "+") { x = ((x += a.x) >= M) ? (x - M) : x; }
      else static if (op == "-") { x = ((x -= a.x) >= M) ? (x + M) : x; }
      else static if (op == "*") { x = cast(uint)((cast(ulong)(x) * a.x) % M); }
      else static if (op == "/") { this *= a.inv(); }
      else static assert(false);
      return this;
    } else static if (op == "^^") {
      if (a < 0) return this = inv()^^(-a);
      ModInt b = this, c = 1U;
      for (long e = a; e; e >>= 1) { if (e & 1) c *= b; b *= b; }
      return this = c;
    } else {
      return mixin("this " ~ op ~ "= ModInt(a)");
    }
  }
  ModInt inv() const {
    uint a = M, b = x; int y = 0, z = 1;
    for (; b; ) { const q = a / b; const c = a - q * b; a = b; b = c; const w = y - cast(int)(q) * z; y = z; z = w; }
    assert(a == 1); return ModInt(y);
  }
  ModInt opUnary(string op)() const {
    static if (op == "+") { return this; }
    else static if (op == "-") { ModInt a; a.x = x ? (M - x) : 0U; return a; }
    else static assert(false);
  }
  ModInt opBinary(string op, T)(T a) const { return mixin("ModInt(this) " ~ op ~ "= a"); }
  ModInt opBinaryRight(string op, T)(T a) const { return mixin("ModInt(a) " ~ op ~ "= this"); }
  bool opCast(T: bool)() const { return (x != 0U); }
  string toString() const { return x.to!string; }
}

enum MO = 998244353;
alias Mint = ModInt!MO;


/*
  >  .  .  s>    >t
  .  >  .   <    < 
  .  .  >   >t  s> 
*/
enum U = 5;
enum int[U][U] TRANS = [
  [1, 1, 1, 1, 0],
  [1, 1, 1, 0, 0],
  [1, 1, 1, 0, 1],
  [0, 0, 1, 1, 0],
  [1, 0, 0, 0, 1],
];

void main() {
  try {
    for (; ; ) {
      const N = readInt;
      const K = readInt;
      
      Mint ans;
      if (N == 1) {
        ans = 1;
      } else {
        auto crt = new Mint[][](U, K + 1);
        void start(int u, int k) {
          if (k <= K) crt[u][k] += 1;
        }
        start(0, 1);
        start(1, 1);
        start(2, 0);
        start(3, 2);
        foreach (i; 1 .. N - 1) {
          auto nxt = new Mint[][](U, K + 1);
          foreach (u; 0 .. U) foreach (v; 0 .. U) if (TRANS[u][v]) {
            int dk;
            if (i % 2 != 0) {
              if (v == 1 || v == 3 || v == 4) ++dk;
              if (v == 2 || v == 3 || v == 4) ++dk;
            } else {
              if (v == 0 || v == 3 || v == 4) ++dk;
              if (v == 1 || v == 3 || v == 4) ++dk;
            }
            foreach (k; 0 .. K - dk + 1) nxt[v][k + dk] += crt[u][k];
          }
          debug if (N <= 10) writeln(nxt);
          crt = nxt;
        }
        foreach (u; [0, 1, 2, (N % 2 != 0) ? 3 : 4]) {
          ans += crt[u].sum;
        }
      }
      writeln(ans);
    }
  } catch (EOFException e) {
  }
}
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