Characters can be encoded via different numbers.
A -> 1, B -> 2, ..., Z -> 26. Given a string
s of numbers, return the number of possible decodings. For example
12 can be decoded as
A,B and as
Given two lists of a
inorder, create a tree and return the
The problem is not so obvious at first. If the preorder list would also contain
null 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
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.
aab can be partitioned as follows:
[['a','a','b'], ['aa','b']]. This is because a single character is by definition a palindrome.
head of a linked list, remove all items with
val. Afterwards, return the new head.