Problem Given a binary tree, return the level of the tree with minimum sum. OR Given the root of a binary tree, the level of its root is 1, the level of its children is 2, and so on. Return the smallest level x such that the sum of all the values of nodes at level x is minimal. Opposite of this problem - Minimum Level Sum of a Binary Tree Problem. ...
Problem Given the root of a binary tree, return the zigzag level order traversal of its nodes’ values. (i.e., from left to right, then right to left for the next level and alternate between). Example Example 1 Tree Traversal Direction 3 -> / \ 9 20 <- / \ 15 7 -> ...
Problem Given the root of a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows: The left subtree of a node contains only nodes with keys less than the node’s key. The right subtree of a node contains only nodes with keys greater than the node’s key. Both the left and right subtrees must also be binary search trees. Examples Example 1: ...
Problem Given the root of a binary tree, the level of its root is 1, the level of its children is 2, and so on. Return the smallest level x such that the sum of all the values of nodes at level x is maximal. Opposite of this problem - Minimum Level Sum of a Binary Tree Problem. Examples Example 1: graph TD A(1) --- B(7) & C(0) B --- D(7) & E("-8") ...
Problem Given a binary tree, print it in vertical order sum Examples Example 1: ...
Problem Implement an algorithm to print all valid (i.e., properly opened and closed) combinations of n-pairs of parentheses. OR Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. Follow up Make sure the returned list of strings are sorted. Examples Example 1: Input: n = 3 Output: ["((()))","(()())","(())()","()(())","()()()"] ...
Problem Given a binary search tree, design an algorithm which creates a linked list of all the nodes at each depth (i.e., if you have a tree with depth D, you’ll have D linked lists) Examples Example 1: Input: 1 / \ 2 3 / \ / \ 4 5 6 7 Output: (1) => NULL (2) => (3) => NULL (4) => (5) => (6) => (7) => NULL ...
Problem Given the root of a binary tree, return the level order traversal of its nodes’ values. (i.e., from left to right, level by level). NOTE : This problem is very similar to - Create linked lists of all the nodes at each depth for a Binary Tree Examples Example 1: 3 / \ 9 20 / \ 15 7 ...
Problem Given a node in a binary tree. Find the rightmost cousin of the give node. Examples Example 1 Let’s start with an example. 1 / \ 2 3 / / \ 4 5 6 \ / 7 8 ...