From fb1d1ea6f9ec402e940e25905e8c69ab08fb4ba0 Mon Sep 17 00:00:00 2001
From: Matej Focko <me@mfocko.xyz>
Date: Tue, 29 Oct 2024 23:36:45 +0100
Subject: [PATCH] =?UTF-8?q?kt:=20add=20=C2=AB2684.=20Maximum=20Number=20of?=
 =?UTF-8?q?=20Moves=20in=20a=20Grid=C2=BB?=
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URL:	https://leetcode.com/problems/maximum-number-of-moves-in-a-grid/
Signed-off-by: Matej Focko <me@mfocko.xyz>
---
 kt/maximum-number-of-moves-in-a-grid.kt | 38 +++++++++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 kt/maximum-number-of-moves-in-a-grid.kt

diff --git a/kt/maximum-number-of-moves-in-a-grid.kt b/kt/maximum-number-of-moves-in-a-grid.kt
new file mode 100644
index 0000000..fd74798
--- /dev/null
+++ b/kt/maximum-number-of-moves-in-a-grid.kt
@@ -0,0 +1,38 @@
+class Solution {
+    fun <A, B> product(
+        xs: Sequence<A>,
+        ys: Sequence<B>,
+    ): Sequence<Pair<A, B>> = xs.flatMap { x -> ys.map { y -> x to y } }
+
+    fun <A, B, C> product(
+        xs: Sequence<A>,
+        ys: Sequence<B>,
+        zs: Sequence<C>,
+    ): Sequence<Triple<A, B, C>> = xs.flatMap { x -> ys.flatMap { y -> zs.map { z -> Triple(x, y, z) } } }
+
+    fun <A, B> product(
+        xs: Iterable<A>,
+        ys: Iterable<B>,
+    ): Sequence<Pair<A, B>> = product(xs.asSequence(), ys.asSequence())
+
+    fun <A, B, C> product(
+        xs: Iterable<A>,
+        ys: Iterable<B>,
+        zs: Iterable<C>,
+    ): Sequence<Triple<A, B, C>> = product(xs.asSequence(), ys.asSequence(), zs.asSequence())
+
+    fun maxMoves(grid: Array<IntArray>): Int {
+        val dp = Array(grid.size) { IntArray(grid[0].size) }
+
+        product(grid[0].indices.reversed().drop(1), grid.indices, -1..1).filter {
+                (x, y, dy) ->
+            y + dy >= 0 && y + dy < dp.size && grid[y][x] < grid[y + dy][x + 1]
+        }.forEach { (x, y, dy) ->
+            dp[y][x] = listOf(dp[y][x], 1 + dp[y + dy][x + 1]).max()
+        }
+
+        return dp.indices.maxOf { y ->
+            dp[y][0]
+        }
+    }
+}