maximum-depth-of-binary-tree

Author: chjung99

maximum-depth-of-binary-tree/chjung99.java

@@ -0,0 +1,51 @@
+import java.util.*;
+
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode() {}
+ *     TreeNode(int val) { this.val = val; }
+ *     TreeNode(int val, TreeNode left, TreeNode right) {
+ *         this.val = val;
+ *         this.left = left;
+ *         this.right = right;
+ *     }
+ * }
+ */
+class Solution {
+    class Data{
+        TreeNode node;
+        int depth;
+        public Data(TreeNode node, int depth){
+            this.node = node;
+            this.depth = depth;
+        }
+    }
+    public int maxDepth(TreeNode root) {
+        return bfs(root);
+    }
+    public int bfs(TreeNode root) {
+        int depth = 0;
+        Queue<Data> q = new ArrayDeque<>();
+        if (root != null){
+            q.add(new Data(root, 1));
+        }
+        while (!q.isEmpty()){
+            Data cur = q.poll();
+            if (cur.depth > depth){
+                depth = cur.depth;
+            }
+            if (cur.node.left != null) {
+                q.add(new Data(cur.node.left, cur.depth + 1));
+            }
+            if (cur.node.right != null) {
+                q.add(new Data(cur.node.right, cur.depth + 1));
+            }
+        }
+        return depth;
+    }
+}
+