結果

問題 No.1507 Road Blocked
ユーザー yakamoto
提出日時 2021-05-14 22:35:09
言語 Kotlin
(2.1.0)
結果
AC  
実行時間 582 ms / 2,000 ms
コード長 5,012 bytes
コンパイル時間 18,662 ms
コンパイル使用メモリ 473,576 KB
実行使用メモリ 79,108 KB
最終ジャッジ日時 2024-10-02 02:27:38
合計ジャッジ時間 35,447 ms
ジャッジサーバーID
(参考情報)
judge3 / judge1
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 * 3
other AC * 30
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:95:9: warning: the value 'u' assigned to 'var v: Int defined in Solver.solve' is never used
        v = u
        ^
Main.kt:200:11: warning: expected performance impact from inlining is insignificant. Inlining works best for functions with parameters of functional types
  private inline fun debug(a: LongArray) {
          ^
Main.kt:204:11: warning: expected performance impact from inlining is insignificant. Inlining works best for functions with parameters of functional types
  private inline fun debug(a: IntArray) {
          ^
Main.kt:208:11: warning: expected performance impact from inlining is insignificant. Inlining works best for functions with parameters of functional types
  private inline fun debug(a: BooleanArray) {
          ^
Main.kt:212:11: warning: expected performance impact from inlining is insignificant. Inlining works best for functions with parameters of functional types
  private inline fun toString(a: BooleanArray) = run{a.map { if (it) 1 else 0 }.joinToString("")}
          ^
Main.kt:214:11: warning: expected performance impact from inlining is insignificant. Inlining works best for functions with parameters of functional types
  private inline fun debugDim(A: Array<LongArray>) {
          ^
Main.kt:221:11: warning: expected performance impact from inlining is insignificant. Inlining works best for functions with parameters of functional types
  private inline fun debugDim(A: Array<IntArray>) {
          ^
Main.kt:228:11: warning: expected performance impact from inlining is insignificant. Inlining works best for functions with parameters of functional types
  private inline fun debugDim(A: Array<BooleanArray>) {
          ^
Main.kt:245:11: warning: expected performance impact from inlining is insignificant. Inlining works best for functions with parameters of functional types
  private inline fun assert(b: Boolean) = run{if (!b) throw AssertionError()}
          ^

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.lang.AssertionError
import java.util.*
import kotlin.math.abs
import kotlin.math.max
import kotlin.math.min
val MOD = 998_244_353
fun packUGraph(n: Int, from: IntArray, to: IntArray): Array<IntArray> {
val p = IntArray(n)
val m = from.size
for (i in 0 until m) {
++p[from[i]]
++p[to[i]]
}
val g = Array(n){IntArray(p[it])}
for (i in 0 until m) {
g[from[i]][--p[from[i]]] = to[i]
g[to[i]][--p[to[i]]] = from[i]
}
return g
}
/**
* (dist, parent, queue)
* @param rt null辿
*/
fun traceBfs(g: Array<IntArray>, rt: Int? = 0): Array<IntArray> {
val n = g.size
val q = IntArray(n)
val d = IntArray(n)
val p = IntArray(n){-2}
var h = 0
var t = 0
fun bfs(rt: Int) {
p[rt] = -1
q[t++] = rt
d[rt] = 0
while (h < t) {
val v = q[h++]
for (i in g[v].indices) { // List<Int>iterator
val u = g[v][i]
if (p[u] == -2) {
p[u] = v
q[t++] = u
d[u] = d[v] + 1
}
}
}
}
if (rt != null) {
bfs(rt)
} else {
for (v in 0 until n) {
if (p[v] != -2) continue
bfs(v)
}
}
return arrayOf(d, p, q)
}
fun powMod(a: Long, n: Long, mod: Int): Long {
if (n == 0L) return 1
val res = powMod(a * a % mod, n / 2, mod)
return if (n % 2 == 1L) res * a % mod else res
}
class Solver(stream: InputStream, private val out: java.io.PrintWriter) {
private val reader = BufferedReader(InputStreamReader(stream), 32768)
fun solve() {
val N = ni()
val (from, to) = na2(N - 1, -1)
val g = packUGraph(N, from, to)
val (_, par, que) = traceBfs(g)
val dp = LongArray(N)
for (i in N - 1 downTo 0) {
val v = que[i]
dp[v]++
for (u in g[v]) {
if (u == par[v]) continue
dp[v] += dp[u]
}
}
debug(dp)
var cnt = 0L
for (i in 0 until N - 1) {
var v = from[i] //
var u = to[i]
if (par[v] == u) {
val t = v
v = u
u = t
}
val n = dp[u] //
val m = N - n
cnt = (cnt + n*(n - 1)/2 + m*(m - 1)/2)%MOD
// debug{"$n $m $cnt"}
}
debug{"$cnt"}
val invn1 = powMod(N.toLong()-1, MOD.toLong()-2, MOD)
val invn = powMod(N.toLong(), MOD.toLong()-2, MOD)
val ans = cnt *invn1% MOD *invn%MOD *invn1%MOD *2%MOD // q = (n-1)*n*(n-1)/2
out.println(ans)
}
private val isDebug = try {
//
System.getenv("MY_DEBUG") != null
} catch (t: Throwable) {
false
}
private var tokenizer: StringTokenizer? = null
private fun next(): String {
while (tokenizer == null || !tokenizer!!.hasMoreTokens()) {
tokenizer = StringTokenizer(reader.readLine())
}
return tokenizer!!.nextToken()
}
private fun ni() = next().toInt()
private fun nl() = next().toLong()
private fun ns() = next()
private fun na(n: Int, offset: Int = 0): IntArray {
return IntArray(n) { ni() + offset }
}
private fun nal(n: Int, offset: Int = 0): LongArray {
val res = LongArray(n)
for (i in 0 until n) {
res[i] = nl() + offset
}
return res
}
private fun na2(n: Int, offset: Int = 0): Array<IntArray> {
val a = Array(2){IntArray(n)}
for (i in 0 until n) {
for (e in a) {
e[i] = ni() + offset
}
}
return a
}
private inline fun debug(msg: () -> String) {
if (isDebug) System.err.println(msg())
}
/**
* debug(dp[1])debug{}
*/
private inline fun debug(a: LongArray) {
debug { a.joinToString(" ") }
}
private inline fun debug(a: IntArray) {
debug { a.joinToString(" ") }
}
private inline fun debug(a: BooleanArray) {
debug { toString(a) }
}
private inline fun toString(a: BooleanArray) = run{a.map { if (it) 1 else 0 }.joinToString("")}
private inline fun debugDim(A: Array<LongArray>) {
if (isDebug) {
for (a in A) {
debug(a)
}
}
}
private inline fun debugDim(A: Array<IntArray>) {
if (isDebug) {
for (a in A) {
debug(a)
}
}
}
private inline fun debugDim(A: Array<BooleanArray>) {
if (isDebug) {
for (a in A) {
debug(a)
}
}
}
/**
* import
*/
private fun hoge() {
min(1, 2)
max(1, 2)
abs(-10)
}
private inline fun assert(b: Boolean) = run{if (!b) throw AssertionError()}
private inline fun assert(b: Boolean, f: () -> String) = run{if (!b) throw AssertionError(f())}
}
fun main() {
val out = java.io.PrintWriter(System.out)
Solver(System.`in`, out).solve()
out.flush()
}
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