count good nodes in binary tree

Author: k-capehart

go/count-good-nodes-in-binary-tree.go

@@ -0,0 +1,40 @@
+package main
+
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */
+func goodNodes(root *TreeNode) int {
+	if root == nil {
+		return 0
+	}
+
+	sum := 1
+	if root.Left != nil {
+		sum = traverse(root.Left, root.Val) + sum
+	}
+	if root.Right != nil {
+		sum = traverse(root.Right, root.Val) + sum
+	}
+	return sum
+}
+
+func traverse(root *TreeNode, maxVal int) int {
+	sum := 0
+	if root.Val >= maxVal {
+		sum++
+		maxVal = root.Val
+	}
+
+	if root.Left != nil {
+		sum = traverse(root.Left, maxVal) + sum
+	}
+	if root.Right != nil {
+		sum = traverse(root.Right, maxVal) + sum
+	}
+	return sum
+}