Maximum Depth of Binary Tree

Author: vfedorovatlas

binary-tree-level-order-traversal/Readme.md

@@ -1,3 +1,3 @@
-# Problem: 135.   Binary Tree Postorder Traversal
+# Problem: 102. Binary Tree Level Order Traversal
 
-Post-order traversal is to traverse the left subtree first. Then traverse the right subtree. Finally, visit the root.
+Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level).

maximum-depth-of-binary-tree/Readme.md

@@ -0,0 +1,5 @@
+# Problem: 104. Maximum Depth of Binary Tree
+
+Given a binary tree, find its maximum depth.
+
+The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

maximum-depth-of-binary-tree/main.go

@@ -0,0 +1,25 @@
+package maximumdepthofbunarytree
+
+// TreeNode data structure
+type TreeNode struct {
+	Val   int
+	Left  *TreeNode
+	Right *TreeNode
+}
+
+func maxDepth(root *TreeNode) int {
+	if root == nil {
+		return 0
+	}
+	left := maxDepth(root.Left)
+	right := maxDepth(root.Right)
+	ret := max(left, right) + 1
+	return ret
+}
+
+func max(a, b int) int {
+	if a < b {
+		return b
+	}
+	return a
+}

maximum-depth-of-binary-tree/main_test.go

@@ -0,0 +1,43 @@
+package maximumdepthofbunarytree
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestMaxDepth(t *testing.T) {
+	testCases := []struct {
+		Input  *TreeNode
+		Output int
+	}{
+		{
+			Input: &TreeNode{
+				Val: 3,
+				Left: &TreeNode{
+					Val: 9,
+				},
+				Right: &TreeNode{
+					Val: 20,
+					Left: &TreeNode{
+						Val: 15,
+					},
+					Right: &TreeNode{
+						Val: 7,
+					},
+				},
+			},
+			Output: 3,
+		},
+		{
+			Input:  nil,
+			Output: 0,
+		},
+	}
+
+	for _, test := range testCases {
+		out := maxDepth(test.Input)
+		if !reflect.DeepEqual(test.Output, out) {
+			t.Errorf("expected to get %#v, but got %#v", test.Output, out)
+		}
+	}
+}