AC https://leetcode-cn.com/problems/copy-list-with-random-pointer

Author: AaronLinRC

src/main/kotlin/leetcode/copy-list-with-random-pointer/Solution.kt

@@ -0,0 +1,84 @@
+package leetcode.`copy-list-with-random-pointer`
+
+class Solution {
+    fun copyRandomList(node: Node?): Node? {
+        node ?: return null
+        var p = node
+        while (p != null) {
+            val copyP = Node(p.`val`)
+            copyP.next = p.next
+            p.next = copyP
+            p = copyP.next
+        }
+        p = node
+        while (p != null) {
+            p.next?.random = p.random?.next
+            p = p.next?.next
+        }
+        p = node
+        var oldNode: Node? = null
+        var result: Node? = null
+        var copyP = result
+        var count = 0
+        while (p != null) {
+            if (count % 2 == 0) {
+                if (oldNode == null) {
+                    oldNode = p
+                } else {
+                    oldNode.next = p
+                    oldNode = oldNode.next
+                }
+            } else {
+                if (result == null) {
+                    result = p
+                    copyP = result
+                } else {
+                    copyP?.next = p
+                    copyP = copyP?.next
+                }
+            }
+            count++
+            p = p.next
+        }
+        oldNode?.next = null
+        copyP?.next = null
+        return result
+    }
+
+
+    //O(N)
+//    fun copyRandomList(node: Node?): Node? {
+//        node ?: return null
+//        var p = node
+//        var head: Node? = null
+//        val map = hashMapOf<Node, Node?>()
+//        var copyP: Node? = null
+//        while (p != null) {
+//            if (head == null) {
+//                head = Node(p.`val`)
+//                copyP = head
+//                map[p] = head
+//            } else {
+//                val copyNode = Node(p.`val`)
+//                map[p] = copyNode
+//                copyP?.next = copyNode
+//                copyP = copyP?.next
+//            }
+//            p = p.next
+//        }
+//        p = node
+//        copyP = head
+//        while (p != null) {
+//            copyP?.random = map[p.random]
+//            copyP = copyP?.next
+//            p = p.next
+//        }
+//        return head
+//    }
+}
+
+
+class Node(var `val`: Int) {
+    var next: Node? = null
+    var random: Node? = null
+}