3365 - Rearrange K Substrings to Form Target String.

Medium

You are given two strings s and t, both of which are anagrams of each other, and an integer k.

Your task is to determine whether it is possible to split the string s into k equal-sized substrings, rearrange the substrings, and concatenate them in any order to create a new string that matches the given string t.

Return true if this is possible, otherwise, return false.

An anagram is a word or phrase formed by rearranging the letters of a different word or phrase, using all the original letters exactly once.

A substring is a contiguous non-empty sequence of characters within a string.

Example 1:

Input: s = "abcd", t = "cdab", k = 2

Output: true

Explanation:

• Split s into 2 substrings of length 2: ["ab", "cd"].

• Rearranging these substrings as ["cd", "ab"], and then concatenating them results in "cdab", which matches t.

Example 2:

Input: s = "aabbcc", t = "bbaacc", k = 3

Output: true

Explanation:

• Split s into 3 substrings of length 2: ["aa", "bb", "cc"].

• Rearranging these substrings as ["bb", "aa", "cc"], and then concatenating them results in "bbaacc", which matches t.

Example 3:

Input: s = "aabbcc", t = "bbaacc", k = 2

Output: false

Explanation:

• Split s into 2 substrings of length 3: ["aab", "bcc"].

• These substrings cannot be rearranged to form t = "bbaacc", so the output is false.

Constraints:

• <code>1 <= s.length == t.length <= 2 * 10⁵</code>

• 1 <= k <= s.length

• s.length is divisible by k.

• s and t consist only of lowercase English letters.

• The input is generated such that s and t are anagrams of each other.