Given two lists of a preorder and inorder, create a tree and return the root node.
preorder: [3,9,20,15,7]
inorder: [9,3,15,20,7]
Resulting tree:
3
/ \
9 20
/ \
15 7null values for the places where the tree does not contain nodes, we could simply iterate over this list and reconstruct the tree from there. But since the null values are missing, we also need to take a look at the inorder list.
Given the root node of a tree, validate whether it is a valid Binary Search Tree. This is a tree where each node is unique, left children are smaller than the root and right children are greater than the root.
Given a string s, return a list containing of all possible partitions of that string that are palindromes. A palindrome is a string that is the same backwards as forwards. For example, abba is a palindrome.
The string aab can be partitioned as follows: [['a','a','b'], ['aa','b']]. This is because a single character is by definition a palindrome.
Given the head of a linked list, remove all items with val. Afterwards, return the new head.
Given an array nums, delete all items that are equal to val. Return the total number of remaining items and perform the deletion in place.