Merge pull request #221

add new problem 27.09

Author: Ashwagandha-coder

contest/src/main/java/com/github/contest/Execute.kt

@@ -1,8 +1,9 @@
 package com.github.contest
 
 
-import com.github.contest.binaryTree.TreeNode
-import com.github.contest.binaryTree.replaceValueInTree
+import com.github.contest.binaryTree.findDuplicateSubtreesProdVariant
+import com.github.contest.binaryTree.printTree
+import com.github.contest.binaryTree.toTreeNode
 import com.github.contest.math.numberOfPowerfulInt
 import com.github.contest.slidingWindow.customStructure.rabinKarpMultiPattern
 import com.github.contest.slidingWindow.customStructure.slidingWindowClassic
@@ -15,18 +16,18 @@ import java.util.TreeMap
  */
 
 fun main() {
+    val tree = listOf(1, 2, 3, 4, null, 2, 4, null, null, 4).toTreeNode()
+    //tree.printTree()
 
-    // 5,4,9,1,10,null,7
-    val root = TreeNode(5)
-    root?.left = TreeNode(4)
-    root?.right = TreeNode(9)
-    root.left?.left = TreeNode(1)
-    root?.left?.right = TreeNode(10)
-    root?.right?.right = TreeNode(7)
+    findDuplicateSubtreesProdVariant(tree).apply {
+        this.forEach {
+            it.printTree()
+        }
+    }
 
-    replaceValueInTree(root).also { println(it) }
 }
 
+
 class Example(val param: String) { // Primary constructor parameter
     init {
         println("init block: $param") // Can access param!

contest/src/main/java/com/github/contest/binaryTree/BinaryTreeAlternativeSolution.kt

@@ -48,6 +48,46 @@ fun isSubtreeSerialization(root: TreeNode?, subRoot: TreeNode?): Boolean {
 fun serialize(root: TreeNode?): String {
     if (root == null) return "null"
 
-    // Use preorder traversal with markers
     return "#${root.`val`} ${serialize(root.left)} ${serialize(root.right)}"
+}
+
+/**
+ * 652. Find Duplicate Subtrees
+ * Alternative Solution
+ * Using Serialize + Traverse
+ */
+
+fun findDuplicateSubtreesOtherSolution(root: TreeNode?): List<TreeNode?> {
+    val result = mutableListOf<TreeNode?>()
+    val subtreeMap = mutableMapOf<String, Int>() // serialization -> count
+    serialize(root, subtreeMap, result)
+    return result
+}
+
+private fun serialize(
+    node: TreeNode?,
+    subtreeMap: MutableMap<String, Int>,
+    result: MutableList<TreeNode?>
+): String {
+    if (node == null) return "#"
+
+    // Postorder serialization: left + right + root
+    val serial = buildString {
+        append(serialize(node.left, subtreeMap, result))
+        append(",")
+        append(serialize(node.right, subtreeMap, result))
+        append(",")
+        append(node.`val`)
+    }
+
+
+    val count = subtreeMap.getOrDefault(serial, 0)
+    subtreeMap[serial] = count + 1
+
+
+    if (count == 1) {
+        result.add(node)
+    }
+
+    return serial
 }

contest/src/main/java/com/github/contest/binaryTree/BinaryTreeLeetcode.kt

@@ -7,10 +7,6 @@ import kotlin.math.abs
  * 1261. Find Elements in a Contaminated Binary Tree
  */
 
-class TreeNode(var `val`: Int) {
-    var left: TreeNode? = null
-    var right: TreeNode? = null
-}
 
 class FindElements(private val root: TreeNode?) {
 
@@ -317,7 +313,7 @@ fun printTree(root: TreeNode?): List<List<String>> {
     val rows = height(root)
     val col = (1 shl rows) - 1
     val res = MutableList(rows) { _ ->
-        MutableList(col) { "" }
+        MutableList(col) { " " }
     }
     val rootPos = (col - 1) / 2
     val queue = LinkedList<Triple<TreeNode, Int, Int>>().apply {
@@ -353,3 +349,59 @@ private fun height(root: TreeNode?): Int = when {
     root == null -> 0
     else -> 1 + maxOf(height(root.left), height(root.right))
 }
+
+/**
+ * 652. Find Duplicate Subtrees
+ */
+
+fun findDuplicateSubtrees(root: TreeNode?): List<TreeNode?> {
+    root ?: return listOf()
+
+    if (root.left == null && root.right == null) return listOf()
+
+    val paths = mutableMapOf<String, Pair<TreeNode, Int>>()
+    val res = mutableListOf<TreeNode?>()
+    val queue = LinkedList<TreeNode>().apply {
+        offer(root)
+    }
+
+    while (queue.isNotEmpty()) {
+        val size = queue.size
+
+        for (i in 0 until size) {
+            val node = queue.poll()
+            val path = serializeDuplicateSubTree(node)
+            if (paths.contains(path)) {
+                val stub = TreeNode(0) to 0
+                paths[path] = paths.getOrDefault(path, stub).let {
+                    it.copy(second = it.second + 1)
+                }
+            } else {
+                paths[path] = Pair(node, 1)
+            }
+
+            node.left?.let {
+                queue.offer(it)
+            }
+
+            node.right?.let {
+                queue.offer(it)
+            }
+        }
+    }
+
+    for ((_, value) in paths) {
+        if (value.second > 1) {
+            res.add(value.first)
+        }
+    }
+
+    return res
+
+}
+
+private fun serializeDuplicateSubTree(root: TreeNode?): String = when {
+    root == null -> "null"
+    else -> "#${root.`val`} , ${serialize(root?.left)} , ${serialize(root?.right)}"
+}
+

contest/src/main/java/com/github/contest/binaryTree/BinaryTreeProdVariant.kt

@@ -77,4 +77,44 @@ fun mergeTreesProdVariant(root1: TreeNode?, root2: TreeNode?): TreeNode? = when
         newRoot.right = mergeTreesProdVariant(root1?.right, root2?.right)
         newRoot
     }
-}
+}
+
+/**
+ * 652. Find Duplicate Subtrees
+ * Prod Variant
+ * Using DFS
+ */
+
+fun findDuplicateSubtreesProdVariant(root: TreeNode?): List<TreeNode?> {
+    val hashToTreeNode = mutableMapOf<String, TreeNode>()
+    return buildList {
+        fun dfs(root: TreeNode?): String {
+            if (root == null) return "#"
+
+            val hash = buildString {
+                append(root.`val`)
+                append(",")
+                append("${dfs(root.left)}")
+                append(",")
+                append("${dfs(root.right)}")
+            }
+
+            add(hash to root)
+            hashToTreeNode[hash] = root
+
+            return hash
+        }
+        dfs(root)
+    }.groupingBy { it.first }
+        .eachCount()
+        .toList()
+        .filter { it.second > 1 }
+        .let { freq ->
+            buildList {
+                freq.forEach {
+                    add(hashToTreeNode[it.first])
+                }
+            }
+        }
+
+}

contest/src/main/java/com/github/contest/binaryTree/TreeNode.kt

@@ -0,0 +1,75 @@
+package com.github.contest.binaryTree
+
+import java.util.LinkedList
+
+class TreeNode(var `val`: Int) {
+    var left: TreeNode? = null
+    var right: TreeNode? = null
+}
+
+fun TreeNode?.printTree() {
+    if (this == null) println("null")
+
+    val printedTree = printTree(this)
+
+    printedTree.forEach {
+        it.joinToString(" ").also { level ->
+            println(level)
+        }
+    }
+}
+
+
+fun List<Int?>.toTreeNode(): TreeNode? {
+
+    val root = TreeNode(this.first()!!)
+    val queue = LinkedList<TreeNode>().apply {
+        offer(root)
+    }
+
+    var i = 1
+
+    while (queue.isNotEmpty() && i < size) {
+        val node = queue.poll()
+
+        if (i < size && this[i] != null) {
+            node.left = TreeNode(this[i]!!)
+            queue.offer(node.left)
+        }
+
+        i++
+
+        if (i < size && this[i] != null) {
+            node.right = TreeNode(this[i]!!)
+            queue.offer(node.right)
+        }
+
+        i++
+    }
+
+    return root
+}
+
+private fun List<Int?>.validationTree(): Unit? {
+    if (isEmpty()) return null
+    if (first() == null) throw IllegalArgumentException("First Element Shouldn't be NULL")
+
+
+    for (i in 0 until size) {
+
+        if (this[i] == null) {
+
+            val leftChildIndex = 2 * i + 1
+            val rightChildIndex = 2 * i + 2
+
+            if (leftChildIndex < size && this[leftChildIndex] != null) throw IllegalArgumentException(
+                "Left subTree shouldn't have child"
+            )
+            if (rightChildIndex < size && this[rightChildIndex] != null) throw IllegalArgumentException(
+                "Right subTree shouldn't have child"
+            )
+        }
+    }
+
+    return Unit
+}