1829: Maximum XOR for Each Query

Author: emanuelschmoczer

README.md

@@ -17,6 +17,7 @@ My solutions to LeetCode problems in Kotlin.
 |                    [206](https://leetcode.com/problems/reverse-linked-list/)                     |                   [Reverse Linked List](src/main/kotlin/com/schmoczer/leetcode/_0206/ReverseLinkedList.kt)                   |    Easy    |
 |                       [344](https://leetcode.com/problems/reverse-string/)                       |                       [Reverse String](src/main/kotlin/com/schmoczer/leetcode/_0344/ReverseString.kt)                        |    Easy    |
 |                       [796](https://leetcode.com/problems/rotate-string/)                        |                        [Rotate String](src/main/kotlin/com/schmoczer/leetcode/_0796/RotateString.kt)                         |    Easy    |
+|                [1829](https://leetcode.com/problems/maximum-xor-for-each-query/)                 |             [Maximum XOR for Each Query](src/main/kotlin/com/schmoczer/leetcode/_1829/MaximumXorForEachQuery.kt)             |   Medium   |
 |          [1957](https://leetcode.com/problems/delete-characters-to-make-fancy-string/)           | [Delete Characters to Make Fancy String](src/main/kotlin/com/schmoczer/leetcode/_1957/DeleteCharactersToMakeFancyString.kt)  |    Easy    |
 |  [2275](https://leetcode.com/problems/largest-combination-with-bitwise-and-greater-than-zero/)   | [Largest Combination With Bitwise AND Greater Than Zero](src/main/kotlin/com/schmoczer/leetcode/_2275/LargestCombination.kt) |   Medium   |
 |                     [2490](https://leetcode.com/problems/circular-sentence/)                     |                    [Circular Sentence](src/main/kotlin/com/schmoczer/leetcode/_2490/CircularSentence.kt)                     |    Easy    |

src/main/kotlin/com/schmoczer/leetcode/_1829/MaximumXorForEachQuery.kt

@@ -0,0 +1,20 @@
+package com.schmoczer.leetcode._1829
+
+import kotlin.math.pow
+
+class MaximumXorForEachQuery {
+    fun getMaximumXor(nums: IntArray, maximumBit: Int): IntArray {
+        val result = IntArray(nums.size) { 0 }
+        var queries = mutableMapOf<Int, Int>()
+        val maxBitsValue = 2.0.pow(maximumBit).toInt() - 1
+
+        for (query in (0 until nums.size).reversed()) {
+            val previous = queries[query + 1] ?: 0
+            val value = nums[nums.size - 1 - query] xor previous
+            queries[query] = value
+            val k = value xor maxBitsValue
+            result[query] = k
+        }
+        return result
+    }
+}

src/main/kotlin/com/schmoczer/leetcode/_1829/README.md

@@ -0,0 +1,36 @@
+# Maximum XOR for Each Query
+
+You are given a sorted array `nums` of `n` non-negative integers and an integer `maximumBit`. You want to perform the
+following query `n` times:
+
+1. Find a non-negative integer `k < 2^maximumBit` such that `nums[0] XOR nums[1] XOR ... XOR nums[nums.length-1] XOR k`
+   is maximized. `k` is the answer to the query number `i`.
+2. Remove the last element from the current array `nums`.
+
+Return an array `answer`, where `answer[i]` is the answer to the `i`-th query.
+
+Example 1:
+
+> Input: nums = [0,1,1,3], maximumBit = 2
+>
+> Output: [0,3,2,3]
+
+Example 2:
+
+> Input: nums = [2,3,4,7], maximumBit = 3
+>
+> Output: [5,2,6,5]
+
+Example 3:
+
+> Input: nums = [0,1,2,2,5,7], maximumBit = 3
+>
+> Output: [4,3,6,4,6,7]
+
+Constraints:
+
+- `nums.length == n`
+- `1 <= n <= 105`
+- `1 <= maximumBit <= 20`
+- `0 <= nums[i] < 2^maximumBit`
+- `nums` is sorted in ascending order.

src/test/kotlin/com/schmoczer/leetcode/_1829/MaximumXorForEachQueryTest.kt

@@ -0,0 +1,34 @@
+package com.schmoczer.leetcode._1829
+
+import org.junit.jupiter.api.BeforeEach
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+
+class MaximumXorForEachQueryTest {
+    private lateinit var sut: MaximumXorForEachQuery
+
+    @BeforeEach
+    fun setUp() {
+        sut = MaximumXorForEachQuery()
+    }
+
+    @Test
+    fun `maximum xor for each query of 0,1,1,3 is 0,3,2,3`() {
+        val input = intArrayOf(0, 1, 1, 3)
+        val expected = intArrayOf(0, 3, 2, 3)
+
+        val result = sut.getMaximumXor(input, 2)
+
+        assertContentEquals(expected, result)
+    }
+
+    @Test
+    fun `maximum xor for each query of 2,3,4,7 is 5,2,6,5`() {
+        val input = intArrayOf(2, 3, 4, 7)
+        val expected = intArrayOf(5, 2, 6, 5)
+
+        val result = sut.getMaximumXor(input, 3)
+
+        assertContentEquals(expected, result)
+    }
+}