1448. Count Good Nodes in Binary Tree

Author: a-khakimov

leetcode-scala/src/main/scala/LeetCode75/BinaryTree_DFS/1448. Count Good Nodes in Binary Tree.sc

@@ -0,0 +1,66 @@
+/**
+ * Definition for a binary tree node.
+ * class TreeNode(_value: Int = 0, _left: TreeNode = null, _right: TreeNode = null) {
+ *   var value: Int = _value
+ *   var left: TreeNode = _left
+ *   var right: TreeNode = _right
+ * }
+ */
+
+class TreeNode(
+  _value: Int = 0,
+  _left: TreeNode = null,
+  _right: TreeNode = null
+) {
+  var value: Int = _value
+  var left: TreeNode = _left
+  var right: TreeNode = _right
+}
+
+
+object Solution {
+  def goodNodes(root: TreeNode): Int = {
+    def dfs(node: TreeNode, max: Int): Int = {
+      if (node == null) 0 else {
+        val isGood = if (node.value >= max) 1 else 0
+        val newMax = Math.max(max, node.value)
+        isGood + dfs(node.left, newMax) + dfs(node.right, newMax)
+      }
+    }
+    dfs(root, Int.MinValue)
+  }
+}
+
+
+
+val tree1 = new TreeNode(3,
+  new TreeNode(5, new TreeNode(6), new TreeNode(7)),
+  new TreeNode(1,
+    new TreeNode(4),
+    new TreeNode(2,
+      new TreeNode(9),
+      new TreeNode(11,
+        new TreeNode(8),
+        new TreeNode(10)
+      )
+    )
+  )
+)
+
+
+val tree2 = new TreeNode(4, new TreeNode(3), new TreeNode(2))
+val tree3 = new TreeNode(
+  2,
+  null,
+  new TreeNode(
+    4,
+    new TreeNode(10),
+    new TreeNode(
+      8,
+      null,
+      new TreeNode(4)
+    )
+  )
+)
+
+Solution.goodNodes(tree3)