Search⌘ K
AI Features

Solution: Additive Number

Explore the backtracking technique to verify if a given numeric string represents an additive number sequence. Understand how to select initial numbers, handle constraints like leading zeros, and apply recursion to confirm the additive property throughout the string. Gain skills in optimizing string partitioning for coding interviews.

Statement

An additive number is a string whose digits can be partitioned into an additive sequence.

A valid additive sequence contains at least three numbers, where every number after the first two is equal to the sum of the two immediately preceding numbers.

Given a string, num, containing only digits, determine whether it represents an additive number. Return TRUE if a valid additive sequence can be formed from the digits of num, and FALSE otherwise.

Note: Numbers in the additive sequence cannot have leading zeros. For example, the sequences 1, 2, 03 and 1, 02, 3 are both invalid.

Constraints:

  • 11 \leq num.length ...