From 7dee18a1ca79e8fa41f0c58d49b7dba4a4419106 Mon Sep 17 00:00:00 2001
From: Matej Focko <me@mfocko.xyz>
Date: Tue, 26 Nov 2024 00:02:35 +0100
Subject: [PATCH] =?UTF-8?q?kt:=20add=20=C2=AB773.=20Sliding=20Puzzle=C2=BB?=
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URL: https://leetcode.com/problems/sliding-puzzle/
Signed-off-by: Matej Focko <me@mfocko.xyz>
---
kt/sliding-puzzle.kt | 63 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 63 insertions(+)
create mode 100644 kt/sliding-puzzle.kt
diff --git a/kt/sliding-puzzle.kt b/kt/sliding-puzzle.kt
new file mode 100644
index 0000000..782e9da
--- /dev/null
+++ b/kt/sliding-puzzle.kt
@@ -0,0 +1,63 @@
+class Solution {
+ companion object {
+ private val DIRECTIONS: List<List<Int>> =
+ listOf(
+ listOf(1, 3),
+ listOf(0, 2, 4),
+ listOf(1, 5),
+ listOf(0, 4),
+ listOf(1, 3, 5),
+ listOf(2, 4),
+ )
+ private val TARGET: String = "123450"
+
+ private fun swap(
+ board: String,
+ i: Int,
+ j: Int,
+ ): String {
+ val cells = board.toMutableList()
+
+ val tmp = cells[i]
+ cells[i] = cells[j]
+ cells[j] = tmp
+
+ return cells.joinToString(separator = "")
+ }
+ }
+
+ fun slidingPuzzle(board: Array<IntArray>): Int {
+ val startState =
+ board.flatMap { it.asSequence() }.joinToString(separator = "") {
+ it.toString()
+ }
+
+ val seen = mutableSetOf<String>(startState)
+ val queue = ArrayDeque<String>(listOf(startState))
+
+ var moves = 0
+ while (queue.isNotEmpty()) {
+ for (i in 1..queue.size) {
+ val current = queue.removeFirst()
+ if (current == TARGET) {
+ return moves
+ }
+
+ val zeroIdx = current.indexOf('0')
+ DIRECTIONS[zeroIdx].forEach {
+ val next = swap(current, zeroIdx, it)
+ if (seen.contains(next)) {
+ return@forEach
+ }
+
+ seen.add(next)
+ queue.addLast(next)
+ }
+ }
+
+ moves += 1
+ }
+
+ return -1
+ }
+}