From 8a7c5f0a843d4284557c190eece91c3df78452f1 Mon Sep 17 00:00:00 2001
From: Matej Focko <me@mfocko.xyz>
Date: Sun, 17 Nov 2024 20:40:55 +0100
Subject: [PATCH] =?UTF-8?q?kt:=20add=20=C2=AB862.=20Shortest=20Subarray=20?=
 =?UTF-8?q?with=20Sum=20at=20Least=20K=C2=BB?=
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URL:	https://leetcode.com/problems/shortest-subarray-with-sum-at-least-k/
Signed-off-by: Matej Focko <me@mfocko.xyz>
---
 kt/shortest-subarray-with-sum-at-least-k.kt | 42 +++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 kt/shortest-subarray-with-sum-at-least-k.kt

diff --git a/kt/shortest-subarray-with-sum-at-least-k.kt b/kt/shortest-subarray-with-sum-at-least-k.kt
new file mode 100644
index 0000000..ce47a4d
--- /dev/null
+++ b/kt/shortest-subarray-with-sum-at-least-k.kt
@@ -0,0 +1,42 @@
+class Solution {
+    fun shortestSubarray(
+        nums: IntArray,
+        k: Int,
+    ): Int {
+        val sums =
+            nums
+                .scan(0L) { runningSum, x ->
+                    runningSum + x.toLong()
+                }
+                .toList()
+
+        val candidates = ArrayDeque<Int>()
+
+        return (0..nums.size)
+            .map { i ->
+                var shortestLength = Int.MAX_VALUE
+                while (
+                    candidates.isNotEmpty() &&
+                    sums[i] - sums[candidates.first()] >= k
+                ) {
+                    shortestLength =
+                        listOf(
+                            shortestLength, i - candidates.removeFirst(),
+                        ).min()
+                }
+
+                while (
+                    candidates.isNotEmpty() &&
+                    sums[i] <= sums[candidates.last()]
+                ) {
+                    candidates.removeLast()
+                }
+
+                candidates.add(i)
+
+                shortestLength
+            }
+            .filter { it < Int.MAX_VALUE }
+            .minOrNull() ?: -1
+    }
+}