結果

問題 No.1749 ラムドスウイルスの感染拡大
ユーザー 箱星
提出日時 2021-10-13 13:21:03
言語 Kotlin
(2.1.0)
結果
AC  
実行時間 603 ms / 2,000 ms
コード長 2,970 bytes
コンパイル時間 13,690 ms
コンパイル使用メモリ 452,892 KB
実行使用メモリ 155,052 KB
最終ジャッジ日時 2024-12-31 18:33:16
合計ジャッジ時間 24,768 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge4
このコードへのチャレンジ
（要ログイン）
ファイルパターン 結果
sample AC * 4
other AC * 26
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.PrintWriter
import java.util.*
import kotlin.math.*

fun PrintWriter.solve() {
    val n = nextInt()
    val m = nextInt()
    val t = nextInt()
    val adj = Array(n) { mutableListOf<Int>() }
    for (i in 0 until m) {
        val v1 = nextInt()
        val v2 = nextInt()
        adj[v1].add(v2)
        adj[v2].add(v1)
    }
    val num = Array(t + 1) { Array(n) { false to ModInt(0) } }
    num[0][0] = true to ModInt(1)
    fun f(i: Int, v: Int): ModInt {
        if (i == 0) return num[i][v].second
        if (num[i][v].first) return num[i][v].second
        var ret = ModInt(0)
        for (w in adj[v]) {
            ret += f(i - 1, w)
        }
        num[i][v] = true to ret
        return ret
    }
    println(f(t, 0))
}

// region ModInt
class ModInt(x: Long) {
    companion object {
        //const val MOD = 1000000007L
        const val MOD = 998244353L
    }

    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", 1.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
0