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Check if Tree is Balanced

Certification: Basic Level Accuracy: 75% Submissions: 4 Points: 5

Write a Java program to determine if a binary tree is balanced. A balanced binary tree is one where the height difference between the left and right subtrees of every node is not more than 1.

Example 1
    

  • Input:
    Tree: 

    Tree Balancing with height Greater than one

    • 

  • Output: true
    • 

  • Explanation:

      

    • Each subtree height difference ≤ 1
      • 

    

    •
Example 2
    

  • Input:

    Tree Balancing with height less than equal to one

    • 

  • Output: false
    • 

  • Explanation:

      

    • Subtree height difference > 1 in some nodes
      • 

    

    •
Constraints
    

  • 0 ≤ number of nodes ≤ 5000
    • 

  • -10^4 ≤ Node.val ≤ 10^4
    • 

  • Time Complexity: O(n)
    • 

  • Space Complexity: O(h)
    •
TreeWalmartSwiggy
Editorial

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Hint
Solution

Solution Hints

    
  
  • Calculate the height of left and right subtrees for each node.
    • 
  
  • Check if the difference between heights is not more than 1.
    • 
  
  • Recursively check balance for left and right subtrees.
    • 
  
  • Use a depth-first approach to traverse the tree.
    • 
  
  • Consider an approach that avoids recalculating heights by calculating height and checking balance in a single traversal.
    •

Steps to solve by this approach:

 Step 1: Define a helper method that checks both height and balance in a single traversal.

 Step 2: For each node, recursively check the height and balance of left and right subtrees.

 Step 3: If a subtree is unbalanced (height difference > 1), return -1 to indicate unbalanced state.

 Step 4: If a subtree is balanced, return its actual height.

 Step 5: For empty nodes (null), return height 0.

 Step 6: At each node, calculate height difference between left and right subtrees.

 Step 7: If the difference exceeds 1, the tree is unbalanced; otherwise, return the height of the current node.

Submitted Code :