count-good-nodes-in-binary-tree

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

@@ -0,0 +1,44 @@
+/*
+ * @lc app=leetcode id=1448 lang=golang
+ *
+ * [1448] Count Good Nodes in Binary Tree
+ */
+package main
+
+// @lc code=start
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */
+import "math"
+
+func goodNodes(root *TreeNode) int {
+	return subGoodNodes(root, math.MinInt)
+}
+
+func subGoodNodes(root *TreeNode, previousMax int) int {
+	if root == nil {
+		return 0
+	}
+	sum := 0
+	max := previousMax
+	if root.Val >= previousMax {
+		sum = 1
+		max = root.Val
+	}
+	sum += subGoodNodes(root.Left, max)
+	sum += subGoodNodes(root.Right, max)
+	return sum
+}
+
+// @lc code=end
+
+type TreeNode struct {
+	Val   int
+	Left  *TreeNode
+	Right *TreeNode
+}