How should I practice Validate a Single-Letter Word Sequence?

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Problem · String

Validate a Single-Letter Word Sequence

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● Easy

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Problem statement

Given an array of strings words, determine whether it forms a valid single-letter word sequence.

The sequence is valid when every adjacent pair has the same length and differs at exactly one character position. A sequence with fewer than two words is valid.

A word may appear again later in the sequence, as long as each adjacent transition still changes exactly one character.

Function

isValidWordSequence(words: String[]) → boolean

Examples

Example 1

words = ["hot","dot","cog"]return = false

hot to dot changes one position, but dot to cog changes two.

Example 2

words = ["hot","dot","dot"]return = false

The final transition changes zero positions, but every adjacent pair must change exactly one.

Example 3

words = ["hot","dot","dog"]return = true

Each adjacent pair has length three and changes exactly one character.

Constraints

0 <= words.length <= 100000.
Every word contains only lowercase English letters.
The total number of characters across all words is at most 200000.