Problem Statement

Given a binary tree and a node, find the level order successor of the given node in the tree. The level order successor is the node that appears right after the given node in the level order traversal.

Example 1:

import java.util.*;
class TreeNode {
  int val;
  TreeNode left;
  TreeNode right;
  TreeNode(int x) {
    val = x;
  }
};
class LevelOrderSuccessor {
  public static TreeNode findSuccessor(TreeNode root, int key) {
    // TODO: Write your code here
    return null;    
  }
  public static void main(String[] args) {
    TreeNode root = new TreeNode(1);
    root.left = new TreeNode(2);
    root.right = new TreeNode(3);
    root.left.left = new TreeNode(4);
    root.left.right = new TreeNode(5);
    
    TreeNode result = LevelOrderSuccessor.findSuccessor(root, 3);
    if (result != null)
      System.out.println(result.val + " ");
    root = new TreeNode(12);
    root.left = new TreeNode(7);
    root.right = new TreeNode(1);
    root.left.left = new TreeNode(9);
    root.right.left = new TreeNode(10);
    root.right.right = new TreeNode(5);
    result = LevelOrderSuccessor.findSuccessor(root, 9);
    if (result != null)
      System.out.println(result.val + " ");
    result = LevelOrderSuccessor.findSuccessor(root, 12);
    if (result != null)
      System.out.println(result.val + " ");
  }
}

Introduction

Pattern: Sliding Window

Pattern: Two Pointers

Pattern: Fast and Slow Patterns

Pattern: Merge Intervals

Pattern: Cyclic Sort

Pattern: In-place Reversal of a LinkedList

Pattern: Tree Breadth First Search

Pattern: Tree Depth First Search

Pattern: Two Heaps

Pattern: Subsets

Pattern: Modified Binary Search

Pattern: Bitwise XOR

Pattern: Top 'K' Elements

Pattern: K-way merge

Pattern : 0/1 Knapsack (Dynamic Programming)

Pattern: Topological Sort (Graph)

Miscellaneous

Conclusions

Level Order Successor (easy)

Problem Statement

Try it yourself

Solution