結果

問題 No.1660 Matrix Exponentiation
ユーザー 箱星箱星
提出日時 2021-07-23 05:29:24
言語 Kotlin
(2.1.0)
結果
RE  
実行時間 -
コード長 2,831 bytes
コンパイル時間 13,672 ms
コンパイル使用メモリ 447,460 KB
実行使用メモリ 110,900 KB
最終ジャッジ日時 2024-11-21 00:08:32
合計ジャッジ時間 30,576 ms
ジャッジサーバーID
(参考情報)
judge3 / judge2
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 * 24 RE * 3
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 #
プレゼンテーションモードにする

import java.io.PrintWriter
import java.util.*
fun PrintWriter.solve() {
val n = nextInt()
val m = nextInt()
val adj = Array(n) { mutableListOf<Int>() }
val set = mutableSetOf<Pair<Int, Int>>()
for (i in 0 until m) {
val v1 = nextInt() - 1
val v2 = nextInt() - 1
if (v1 == v2 || set.contains(v2 to v1)) {
println(-1)
return
}
adj[v1].add(v2)
set.add(v1 to v2)
}
if (findCycle(adj).isNotEmpty()) {
println(-1)
} else {
val lst = topologicalSort(adj)
val dp = IntArray(n) { -1 }
fun dfs(v: Int): Int {
if (dp[v] != -1) return dp[v]
var max = 0
for (w in adj[v]) {
max = maxOf(max, dfs(w))
}
dp[v] = max + 1
return dp[v]
}
lst.forEach { dfs(it) }
println(dp.maxOrNull()!!)
}
}
fun findCycle(adj: Array<MutableList<Int>>): List<Int> {
val n = adj.size
val seen = BooleanArray(n) { false }
val finished = BooleanArray(n) { false }
var pos = -1
val hist = Stack<Int>()
fun dfs(v: Int, p: Int) {
seen[v] = true
hist.push(v)
for (w in adj[v]) {
if (w == p) continue
if (finished[w]) continue
if (seen[w] && !finished[w]) {
pos = w
return
}
dfs(w, v)
if (pos != -1) return
}
hist.pop()
finished[v] = true
}
for (i in 0 until n) {
if (!finished[i]) {
dfs(i, -1)
if (pos != -1) break
}
}
val cycle = mutableListOf<Int>()
while (hist.isNotEmpty()) {
val t = hist.pop()
cycle.add(t)
if (t == pos) break
}
return cycle
}
fun topologicalSort(adj: Array<MutableList<Int>>): List<Int> {
val ans = mutableListOf<Int>()
val n = adj.size
val ind = IntArray(n) { 0 }
for (i in 0 until n) {
for (v in adj[i]) ind[v]++
}
val que: Queue<Int> = ArrayDeque()
for (i in 0 until n) {
if (ind[i] == 0) que.add(i)
}
while (que.isNotEmpty()) {
val now = que.poll()
ans.add(now)
for (v in adj[now]) {
ind[v]--
if (ind[v] == 0) que.add(v)
}
}
return ans
}
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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