Apr 9, 2022 · Apr 8, 2022 · Apr 9, 2022
diff --git a/java/543-Diameter-of-Binary-Tree.java b/java/543-Diameter-of-Binary-Tree.java
 class Solution {
      private static int treeDiameter = 0;

    public int diameterOfBinaryTree(TreeNode root) {
   calculateHeight(root);
    return treeDiameter-1;
  }

  private static int calculateHeight(TreeNode currentNode) {
    if (currentNode == null)
      return 0;

    int leftTreeHeight = calculateHeight(currentNode.left);
    int rightTreeHeight = calculateHeight(currentNode.right);

    // if the current node doesn't have a left or right subtree, we can't have
    // a path passing through it, since we need a leaf node on each side
    if (leftTreeHeight != 0 && rightTreeHeight != 0) {

      // diameter at the current node will be equal to the height of left subtree +
      // the height of right sub-trees + '1' for the current node
      int diameter = leftTreeHeight + rightTreeHeight + 1;

      // update the global tree diameter
      treeDiameter = Math.max(treeDiameter, diameter);
    }

    // height of the current node will be equal to the maximum of the heights of
    // left or right subtrees plus '1' for the current node
    return Math.max(leftTreeHeight, rightTreeHeight) + 1;
  }
 }
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,32 @@
		class Solution {
		private static int treeDiameter = 0;

		public int diameterOfBinaryTree(TreeNode root) {
		calculateHeight(root);
		return treeDiameter-1;
		}

		private static int calculateHeight(TreeNode currentNode) {
		if (currentNode == null)
		return 0;

		int leftTreeHeight = calculateHeight(currentNode.left);
		int rightTreeHeight = calculateHeight(currentNode.right);

		// if the current node doesn't have a left or right subtree, we can't have
		// a path passing through it, since we need a leaf node on each side
		if (leftTreeHeight != 0 && rightTreeHeight != 0) {

		// diameter at the current node will be equal to the height of left subtree +
		// the height of right sub-trees + '1' for the current node
		int diameter = leftTreeHeight + rightTreeHeight + 1;

		// update the global tree diameter
		treeDiameter = Math.max(treeDiameter, diameter);
		}

		// height of the current node will be equal to the maximum of the heights of
		// left or right subtrees plus '1' for the current node
		return Math.max(leftTreeHeight, rightTreeHeight) + 1;
		}
		}