結果

問題 No.1740 Alone 'a'
ユーザー 箱星
提出日時 2021-11-12 22:43:06
言語 Kotlin
(2.1.0)
結果
AC  
実行時間 504 ms / 2,000 ms
コード長 3,028 bytes
コンパイル時間 15,978 ms
コンパイル使用メモリ 451,896 KB
実行使用メモリ 111,420 KB
最終ジャッジ日時 2024-11-25 20:24:52
合計ジャッジ時間 33,994 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge3
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 38
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 #
プレゼンテーションモードにする

import java.io.PrintWriter
import java.util.*
import kotlin.math.*
fun PrintWriter.solve() {
    val n = nextInt()
    val s = nextLine()
    val dp = Array(n + 1) { Array(2) { Array(2) { ModInt(0) } } }
    dp[0][0][0] = ModInt(1)
    for (i in 0 until n) {
        val c = s[i]
        dp[i + 1][0][0] = if (c == 'a') ModInt(0) else dp[i][0][0]
        dp[i + 1][0][1] = if (c == 'a') dp[i][0][0] else dp[i][0][1]
        dp[i + 1][1][0] = if (c == 'a') dp[i][1][0] * ModInt(25)
                            else dp[i][1][0] * ModInt(25) + dp[i][0][0] * ModInt(c - 'b')
        dp[i + 1][1][1] = if (c == 'a') dp[i][1][1] * ModInt(25) + dp[i][1][0]
                            else dp[i][1][1] * ModInt(25) + dp[i][1][0] + dp[i][0][0] + dp[i][0][1] * ModInt(c - 'b')
    }
    println(dp[n][1][1])
}
// region ModInt
class ModInt(x: Long) {
    companion object {
        const val MOD = 998244353L
        //const val MOD = 1000000007L
    }
    constructor(y: Int) : this(y.toLong())
    val x = (x % MOD + MOD) % MOD
    operator fun plus(other: ModInt): ModInt {
        return ModInt(x + other.x)
    }
    operator fun minus(other: ModInt): ModInt {
        return ModInt(x - other.x)
    }
    operator fun times(other: ModInt): ModInt {
        return ModInt(x * other.x)
    }
    operator fun div(other: ModInt): ModInt {
        return this * other.inv()
    }
    fun pow(exp: Long): ModInt {
        if (exp == 0L) return ModInt(1L)
        var a = pow(exp shr 1)
        a *= a
        if (exp and 1L == 0L) return a
        return this * a
    }
    fun inv(): ModInt {
        return this.pow(MOD - 2)
    }
    override fun equals(other: Any?): Boolean {
        if (this === other) return true
        if (javaClass != other?.javaClass) return false
        other as ModInt
        if (x != other.x) return false
        return true
    }
    override fun hashCode(): Int {
        return x.hashCode()
    }
    override fun toString(): String {
        return "$x"
    }
}
fun Long.toModInt(): ModInt {
    return ModInt(this)
}
fun Int.toModInt(): ModInt {
    return ModInt(this)
}
fun binomSimple(n: Long, k: Long): ModInt {
    var numer = ModInt(1)
    var denom = ModInt(1)
    for (i in 0 until k) {
        numer *= ModInt(n - i)
        denom *= ModInt(k - i)
    }
    return numer / denom
}
// endregion
fun main() {
    Thread(null, {
        val writer = PrintWriter(System.out, false)
        writer.solve()
        writer.flush()
    }, "solve", abs(1L.shl(26)))
        .apply { setUncaughtExceptionHandler { _, e -> e.printStackTrace(); kotlin.system.exitProcess(1) } }
        .apply { start() }.join()
}
// region Scanner
private var st = StringTokenizer("")
private val br = System.`in`.bufferedReader()
fun next(): String {
    while (!st.hasMoreTokens()) st = StringTokenizer(br.readLine())
    return st.nextToken()
}
fun nextInt() = next().toInt()
fun nextLong() = next().toLong()
fun nextLine() = br.readLine()
fun nextDouble() = next().toDouble()
// endregion
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