104 finish

思维定式害死人

Author: aQua

Algorithms/0104.maximum-depth-of-binary-tree/maximum-depth-of-binary-tree.go

@@ -7,24 +7,16 @@ import (
 type TreeNode = kit.TreeNode
 
 func maxDepth(root *TreeNode) int {
-	res := 0 
-
-	var dfs func(*TreeNode, int)
-	dfs = func(root *TreeNode, level int) {
-		if root == nil {
-			return
-		}
-
-		// 出现了新的 level
-		if res < level {
-			res = level
-		}
-
-		dfs(root.Left, level+1)
-		dfs(root.Right, level+1)
+	if root == nil {
+		return 0
 	}
 
-	dfs(root, 1)
+	return 1 + max(maxDepth(root.Left), maxDepth(root.Right))
+}
 
-	return res
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
 }

Algorithms/0104.maximum-depth-of-binary-tree/maximum-depth-of-binary-tree_test.go

@@ -30,6 +30,12 @@ func Test_Problem0104(t *testing.T) {
 			3,
 		},
 
+		{
+			[]int{3, 9, 20, 15, 10, 7},
+			[]int{9, 3, 10, 15, 20, 7},
+			4,
+		},
+
 		// 可以多个 testcase
 	}