UTF-8 Validation

Challenge Points: 20

Level: Medium

You are given an array data, where each value represents a single byte. The task is to determine whether these bytes together form a correct UTF-8 encoded sequence.

A UTF-8 character can be represented using 1 to 4 bytes, and each character follows specific bit patterns:

Character Length	Byte Format (binary)
1 byte	`0xxxxxxx`
2 bytes	`110xxxxx 10xxxxxx`
3 bytes	`1110xxxx 10xxxxxx 10xxxxxx`
4 bytes	`11110xxx 10xxxxxx 10xxxxxx 10xxxxxx`

The first byte determines how many total bytes the character uses.
Every continuation byte must start with 10.

You must return true if the entire array follows valid UTF-8 encoding rules; otherwise, return false.

Example 1:

Input: data = [65]

Output: true

Explanation:

65 → 01000001 which matches the 1-byte UTF-8 format.

Example 2:

Input: data = [240, 162, 138, 147]

Output: true

Explanation:

240 → 11110000 → indicates a 4-byte character. All following bytes begin with 10, so the sequence is valid.

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