Create LC_1681.kt

Author: murane

LC_1681.kt

@@ -0,0 +1,47 @@
+import kotlin.math.abs
+
+class Solution {
+    private var min = Int.MAX_VALUE
+    private var bucketSize = 0
+
+    fun minimumIncompatibility(nums: IntArray, k: Int): Int {
+        val n = nums.size
+        bucketSize = n / k
+        val sets: MutableList<MutableSet<Int>> = ArrayList()
+        for (i in 0 until k) {
+            sets.add(HashSet())
+        }
+        backtrack(nums, 0, sets, 0)
+        return if (min == Int.MAX_VALUE) -1 else min
+    }
+
+    private fun backtrack(nums: IntArray, idx: Int, sets: List<MutableSet<Int>>, acc: Int) {
+        var acc = acc
+        if (idx >= nums.size) {
+            min = min.coerceAtMost(acc)
+            return
+        }
+        val visited: MutableSet<Set<Int>> = HashSet()
+        for (set in sets) {
+            if (set.contains(nums[idx]) || set.size == bucketSize || visited.contains(set)) continue
+            val impact = computeImpact(set, nums[idx])
+            acc += impact
+            if (acc < min) {
+                set.add(nums[idx])
+                backtrack(nums, idx + 1, sets, acc)
+                set.remove(nums[idx])
+            }
+            acc -= impact
+            visited.add(set)
+        }
+    }
+
+    private fun computeImpact(set: Set<Int>, num: Int): Int {
+        if (set.isEmpty()) return 0
+        if (set.size == 1) return abs(num - set.first())
+        val lo = set.min()!!
+        val hi = set.max()!!
+        if (num < lo) return lo - num
+        return if (num > hi) num - hi else 0
+    }
+}