maximum depth of binary tree

Author: sonjh1217

maximum-depth-of-binary-tree/sonjh1217.swift

@@ -0,0 +1,42 @@
+class Solution {
+    func maxDepthStack(_ root: TreeNode?) -> Int {
+        guard let root = root else {
+            return 0
+        }
+        var searchStack = [(TreeNode, Int)]()
+        searchStack.append((root, 1))
+        var maxDepth = 1
+
+        while searchStack.isEmpty == false {
+            guard let popped = searchStack.popLast() else {
+                break
+            }
+            maxDepth = max(popped.1, maxDepth)
+            
+            if let left = popped.0.left {
+                searchStack.append((left, popped.1 + 1))
+            }
+            
+            if let right = popped.0.right {
+                searchStack.append((right, popped.1 + 1))
+            }
+        }
+        
+        return maxDepth
+        
+        //시간복잡도 O(n)
+        //공간복잡도 O(n)
+    }
+    
+    func maxDepthRecursion(_ root: TreeNode?) -> Int {
+        guard let root = root else {
+            return 0
+        }
+        
+        return max(maxDepth(root.left), maxDepth(root.right)) + 1
+        
+        //시간복잡도 O(n)
+        //공간복잡도 O(n)
+    }
+}
+