結果

問題 No.1582 Vertexes vs Edges
コンテスト
ユーザー 箱星
提出日時 2021-07-02 22:26:35
言語 Kotlin
(2.1.0)
結果
WA  
実行時間 -
コード長 2,758 bytes
コンパイル時間 14,576 ms
コンパイル使用メモリ 446,972 KB
実行使用メモリ 103,732 KB
最終ジャッジ日時 2024-06-29 12:15:00
合計ジャッジ時間 29,475 ms
ジャッジサーバーID
（参考情報） 		judge1 / 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 * 3 WA * 33
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.*

fun PrintWriter.solve() {
    val n = nextInt()
    val adj = Array(n) { mutableListOf<Int>() }
    for (i in 0 until n - 1) {
        val v1 = nextInt() - 1
        val v2 = nextInt() - 1
        adj[v1].add(v2)
        adj[v2].add(v1)
    }
    val color = Array(n) { 0 }
    color[0] = 1
    val stack = Stack<Pair<Int, Int>>()
    stack.push(0 to -1)
    while (stack.isNotEmpty()) {
        val (v, p) = stack.pop()
        if (p != -1) {
            color[v] = -color[p]
        }
        for (w in adj[v]) {
            if (w != p) {
                stack.push(w to v)
            }
        }
    }
    val c1 = color.count { it == 1 }
    val c2 = n - c1
    println(minOf(c1, c2))
}

// 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() {
    val writer = PrintWriter(System.out, false)
    writer.solve()
    writer.flush()
}

// 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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