Merge pull request #2298 from yaxarat/kotlin-280

Add 0280-wiggle-sort.kt

Author: a93a

kotlin/0280-wiggle-sort.kt

@@ -0,0 +1,19 @@
+class Solution {
+    fun wiggleSort(nums: IntArray): Unit {
+        for (i in 1 .. nums.lastIndex) {
+            val prev = nums[i - 1]
+            val curr = nums[i]
+
+            when (i % 2) {
+                0 -> { if (prev < curr) nums.swap(i) }
+                else -> { if (prev > curr) nums.swap(i) }
+            }
+        }
+    }
+
+    private fun IntArray.swap(currentIndex: Int) {
+        this[currentIndex - 1] = this[currentIndex].also { 
+            this[currentIndex] = this[currentIndex - 1] 
+        }
+    }
+}