tree functions segregation

src/com/dsa/trees/DepthFirstTraversal.java

@@ -0,0 +1,61 @@
+package com.dsa.trees;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Queue;
+
+public class DepthFirstTraversal {
+    public static void main(String[] args) {
+        try (BufferedReader reader = new BufferedReader(new FileReader("input.txt"))) {
+            String[] elements = reader.readLine().trim().split(",");
+            Queue<TreeNode> queue = new LinkedList<>();
+            TreeNode root = new TreeNode(Integer.parseInt(elements[0]));
+            queue.offer(root);
+            int index = 1;
+            while (!queue.isEmpty() && index < elements.length) {
+                TreeNode node = queue.poll();
+                if (!elements[index].equalsIgnoreCase("null")) {
+                    node.left = new TreeNode(Integer.parseInt(elements[index]));
+                    queue.offer(node.left);
+                }
+                index++;
+                if (!elements[index].equalsIgnoreCase("null")) {
+                    node.right = new TreeNode(Integer.parseInt(elements[index]));
+                    queue.offer(node.right);
+                }
+                index++;
+            }
+            System.out.println("MinDepth: " + minDepth(root));
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private static int diameter = 0;
+    public static int diameterOfBinaryTree(TreeNode root) {
+        diameter = 0;
+        if (root == null) return 0;
+        heightOfBT(root);
+        return diameter - 1;
+    }
+
+    public static int heightOfBT(TreeNode root) {
+        if (root == null) return 0;
+        int leftHeight = heightOfBT(root.left);
+        int rightHeight = heightOfBT(root.right);
+        diameter = Math.max(leftHeight + rightHeight + 1, diameter);
+        return Math.max(leftHeight, rightHeight) + 1;
+    }
+
+    public static int minDepth(TreeNode root) {
+        if(root == null) return 0;
+        int leftHeight = minDepth(root.left);
+        int rightHeight = minDepth(root.right);
+        if (leftHeight == 0) return rightHeight + 1;
+        if (rightHeight == 0) return leftHeight + 1;
+        return Math.min(leftHeight, rightHeight) + 1;
+    }
+}

src/com/dsa/trees/LevelOrderTraversal.java

@@ -32,7 +32,6 @@ public class LevelOrderTraversal {
             for (List<Integer> level : list) {
                 System.out.println(level);
             }
-            System.out.println("MinDepth: " + minDepth(root));
         } catch (IOException e) {
             throw new RuntimeException(e);
         }
@@ -75,29 +74,4 @@ public class LevelOrderTraversal {
         }
         return res;
     }
-
-    private static int diameter = 0;
-    public static int diameterOfBinaryTree(TreeNode root) {
-        diameter = 0;
-        if (root == null) return 0;
-        heightOfBT(root);
-        return diameter - 1;
-    }
-
-    public static int heightOfBT(TreeNode root) {
-        if (root == null) return 0;
-        int leftHeight = heightOfBT(root.left);
-        int rightHeight = heightOfBT(root.right);
-        diameter = Math.max(leftHeight + rightHeight + 1, diameter);
-        return Math.max(leftHeight, rightHeight) + 1;
-    }
-
-    public static int minDepth(TreeNode root) {
-        if(root == null) return 0;
-        int leftHeight = minDepth(root.left);
-        int rightHeight = minDepth(root.right);
-        if (leftHeight == 0) return rightHeight + 1;
-        if (rightHeight == 0) return leftHeight + 1;
-        return Math.min(leftHeight, rightHeight) + 1;
-    }
 }