結果

問題 No.1081 和の和
ユーザー 箱星
提出日時 2020-06-19 21:24:09
言語 Kotlin
(2.1.0)
結果
AC  
実行時間 296 ms / 2,000 ms
コード長 2,923 bytes
コンパイル時間 13,997 ms
コンパイル使用メモリ 457,744 KB
実行使用メモリ 56,924 KB
最終ジャッジ日時 2024-07-03 13:40:57
合計ジャッジ時間 17,796 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge5
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 * 8
権限があれば一括ダウンロードができます
コンパイルメッセージ
Main.kt:111:10: warning: parameter 'args' is never used
fun main(args: Array<String>) {
         ^

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.BufferedReader
import java.io.InputStream
import java.io.InputStreamReader
import java.io.PrintWriter
import java.lang.IllegalArgumentException
import java.lang.StringBuilder
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 a = Array(n) { sc.nextInt() }
    var ans = ModInt(0)
    for (i in 0 until n) {
        ans += ModInt(a[i].toLong()) * comb(n - 1L, i.toLong())
    }
    println(ans)
}
fun main(args: Array<String>) {
    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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