Created
March 11, 2021 08:23
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import kotlin.math.roundToInt | |
import kotlin.time.ExperimentalTime | |
import kotlin.time.TimeSource | |
private const val MOD = 998244353 | |
private fun mul(a: Int, b: Int) = (a.toLong() * b % MOD).toInt() | |
@OptIn(ExperimentalTime::class) | |
fun main() { | |
val start = TimeSource.Monotonic.markNow() | |
val n = 400 | |
val d = Array(n) { IntArray(n) { Int.MAX_VALUE / 2 } } | |
for (i in 0 until n) { | |
d[i][i] = 0 | |
} | |
val m = n - 1 | |
val g = Graph(n, 2 * m) | |
repeat(m) { | |
val a = it | |
val b = it + 1 | |
d[a][b] = 1 | |
d[b][a] = 1 | |
g.add(a, b) | |
g.add(b, a) | |
} | |
for (k in 0 until n) { | |
for (i in 0 until n) { | |
for (j in 0 until n) { | |
val s = d[i][k] + d[k][j] | |
if (s < d[i][j]) d[i][j] = s | |
} | |
} | |
} | |
for (x in 0 until n) { | |
val row = IntArray(n) { y -> | |
var prod = 1 | |
val dx = d[x] | |
val xy = dx[y] | |
for (k in 0 until n) if (k != x) { | |
val dy = d[y] | |
val xk = dx[k] | |
val yk = dy[k] | |
var cnt = 0 | |
var cntMid = 0 | |
g.from(k) { t -> | |
val xt = dx[t] | |
val yt = dy[t] | |
if (xt == xk - 1) when (yt) { | |
yk - 1 -> { | |
cnt++ | |
} | |
yk + 1 -> { | |
if (xk + yk == xy) { | |
cntMid++ | |
cnt++ | |
} | |
} | |
} | |
} | |
if (cntMid > 1 || cnt == 0) { | |
prod = 0 | |
break | |
} else { | |
prod = mul(prod, cnt) | |
} | |
} | |
prod | |
} | |
// println(row.joinToString(" ")) | |
for (i in 0 until n) { | |
check(row[i] == 1) | |
} | |
} | |
println("Done in ${start.elapsedNow().inMilliseconds.roundToInt()} ms") | |
} | |
class Graph(vCap: Int = 16, eCap: Int = vCap * 2) { | |
var vCnt = 0 | |
var eCnt = 0 | |
var vHead = IntArray(vCap) { -1 } | |
var eVert = IntArray(eCap) | |
var eNext = IntArray(eCap) | |
fun add(v: Int, u: Int, e: Int = eCnt++) { | |
ensureVCap(maxOf(v, u) + 1) | |
ensureECap(e + 1) | |
eVert[e] = u | |
eNext[e] = vHead[v] | |
vHead[v] = e | |
} | |
inline fun from(v: Int, action: (u: Int) -> Unit) { | |
var e = vHead[v] | |
while (e >= 0) { | |
action(eVert[e]) | |
e = eNext[e] | |
} | |
} | |
private fun ensureVCap(vCap: Int) { | |
if (vCap <= vCnt) return | |
vCnt = vCap | |
if (vCap > vHead.size) { | |
val newSize = maxOf(2 * vHead.size, vCap) | |
vHead = vHead.copyOf(newSize) | |
} | |
} | |
private fun ensureECap(eCap: Int) { | |
if (eCap <= eCnt) return | |
eCnt = eCap | |
if (eCap > eVert.size) { | |
val newSize = maxOf(2 * eVert.size, eCap) | |
eVert = eVert.copyOf(newSize) | |
eNext = eNext.copyOf(newSize) | |
} | |
} | |
} |
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