Maximum depth of n-ary tree.

Author: recherst

Easy/559.Maximum Depth of N-ary Tree.playground/Contents.swift

@@ -0,0 +1,51 @@
+/**
+ Given a n-ary 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.
+
+ Nary-Tree input serialization is represented in their level order traversal, each group of children is separated by the null value (See examples).
+
+  
+
+ Example 1:
+ Input: root = [1,null,3,2,4,null,5,6]
+ Output: 3
+ 
+ Example 2:
+ Input: root = [1,null,2,3,4,5,null,null,6,7,null,8,null,9,10,null,null,11,null,12,null,13,null,null,14]
+ Output: 5
+  
+
+ Constraints:
+ - The total number of nodes is in the range [0, 104].
+ - The depth of the n-ary tree is less than or equal to 1000.
+ */
+/**
+ * Definition for a Node.
+ */
+public class Node {
+    public var val: Int
+    public var children: [Node]
+    public init(_ val: Int) {
+        self.val = val
+        self.children = []
+    }
+}
+class Solution {
+    func maxDepth(_ root: Node?) -> Int {
+        if root?.val == nil { return 0 }
+        var depth = 0
+        for child in root!.children {
+            depth = max(depth, maxDepth(child))
+        }
+        return depth + 1
+    }
+}
+
+let s = Solution()
+let node = Node(1)
+let node1 = Node(3)
+node1.children = [Node(5), Node(6)]
+node.children = [node1, Node(2), Node(4)]
+let r = s.maxDepth(node)
+print(r)

Easy/559.Maximum Depth of N-ary Tree.playground/contents.xcplayground

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+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='ios' buildActiveScheme='true' importAppTypes='true'>
+    <timeline fileName='timeline.xctimeline'/>
+</playground>

Easy/559.Maximum Depth of N-ary Tree.playground/playground.xcworkspace/contents.xcworkspacedata

@@ -110,6 +110,7 @@
 106. [Reverse String II](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/541.Reverse%20String%20II.playground/Contents.swift)
 107. [Student Attendance Record I](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/551.Student%20Attendance%20Record%20I.playground/Contents.swift)
 108. [Reverse Words in a String III](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/557.Reverse%20Words%20in%20a%20String%20III.playground/Contents.swift)
+109. [Maximum Depth of N-ary Tree](https://github.com/recherst/leetcode-algtorithm/blob/main/Easy/559.Maximum%20Depth%20of%20N-ary%20Tree.playground/Contents.swift)
 
 #### Medium