結果

問題 No.1428 PeRmutation Question
ユーザー 👑 箱
提出日時 2020-10-01 20:27:04
言語 Kotlin
(1.9.10)
結果
AC  
実行時間 624 ms / 2,000 ms
コード長 3,336 bytes
コンパイル時間 16,232 ms
コンパイル使用メモリ 429,560 KB
実行使用メモリ 64,800 KB
最終ジャッジ日時 2023-07-25 00:31:50
合計ジャッジ時間 35,280 ms
ジャッジサーバーID
(参考情報)
judge13 / judge14
このコードへのチャレンジ(β)

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 239 ms
52,580 KB
testcase_01 AC 252 ms
52,580 KB
testcase_02 AC 274 ms
52,620 KB
testcase_03 AC 267 ms
52,552 KB
testcase_04 AC 247 ms
52,364 KB
testcase_05 AC 245 ms
52,676 KB
testcase_06 AC 276 ms
52,528 KB
testcase_07 AC 240 ms
52,528 KB
testcase_08 AC 254 ms
53,164 KB
testcase_09 AC 245 ms
53,192 KB
testcase_10 AC 252 ms
52,468 KB
testcase_11 AC 259 ms
52,656 KB
testcase_12 AC 351 ms
56,036 KB
testcase_13 AC 624 ms
60,576 KB
testcase_14 AC 491 ms
60,524 KB
testcase_15 AC 496 ms
58,252 KB
testcase_16 AC 527 ms
62,876 KB
testcase_17 AC 525 ms
64,644 KB
testcase_18 AC 409 ms
58,160 KB
testcase_19 AC 398 ms
56,200 KB
testcase_20 AC 406 ms
56,268 KB
testcase_21 AC 509 ms
62,560 KB
testcase_22 AC 522 ms
64,704 KB
testcase_23 AC 542 ms
64,428 KB
testcase_24 AC 528 ms
64,760 KB
testcase_25 AC 523 ms
62,440 KB
testcase_26 AC 507 ms
62,844 KB
testcase_27 AC 536 ms
64,448 KB
testcase_28 AC 518 ms
62,376 KB
testcase_29 AC 546 ms
64,440 KB
testcase_30 AC 536 ms
64,800 KB
testcase_31 AC 536 ms
64,704 KB
testcase_32 AC 509 ms
64,464 KB
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 java.io.BufferedReader
import java.io.InputStream
import java.io.InputStreamReader
import java.io.PrintWriter
import java.util.*

// ModInt
// region
class ModInt(x: Long) {

    companion object {
        const val MOD = 1000000007L
        //const val MOD = 998244353L
    }

    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"
    }

}

val fac = mutableListOf<ModInt>()
val invfac = mutableListOf<ModInt>()

fun fact(n: Long, b: Boolean): ModInt {
    if (fac.count() == 0) {
        fac.add(ModInt(1))
        invfac.add(ModInt(1))
    }
    while (fac.count() <= n) {
        fac.add(fac.last() * ModInt(fac.count().toLong()))
        invfac.add(fac.last().inv())
    }
    return if (b) {
        fac[n.toInt()]
    } else {
        invfac[n.toInt()]
    }
}

fun comb(n: Long, k: Long): ModInt {
    return fact(n, true) * fact(k, false) * fact(n - k, false)
}

fun comb2(n: Long, k: Long): ModInt {
    var ans = ModInt(1)
    for (i in 0 until k) {
        ans = ans * ModInt(n - i) / ModInt(k - i)
    }
    return ans
}
// endregion

fun PrintWriter.solve(sc: FastScanner) {
    val n = sc.nextInt()
    val p = Array(n) { sc.nextInt() - 1 }
    val map = mutableMapOf<Int, Int>()
    val visited = Array(n) { false }
    for (i in 0 until n) {
        if (!visited[i]) {
            var l = 0
            var v = i
            while (!visited[v]) {
                visited[v] = true
                v = p[v]
                l++
            }
            map[l] = (map[l] ?: 0) + 1
        }
    }
    var half = true
    var ans = fact(n.toLong(), true)
    for ((k, v) in map) {
        if (k % 2 == 0 || v >= 2) half = false
        ans /= ModInt(k.toLong()).pow(v.toLong())
        ans *= fact(v.toLong(), false)
    }
    if (half && n != 1) ans /= ModInt(2)
    println(ans)
}

fun main() {
    val writer = PrintWriter(System.out, false)
    writer.solve(FastScanner(System.`in`))
    writer.flush()
}

class FastScanner(s: InputStream) {
    private var st = StringTokenizer("")
    private val br = BufferedReader(InputStreamReader(s))

    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()
    fun ready() = br.ready()
}
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