Explain your approach in three sentences only at top of your code

Given an array of strings, group anagrams together.

Example: Input: ["eat", "tea", "tan", "ate", "nat", "bat"], Output: [ ["ate","eat","tea"], ["nat","tan"], ["bat"] ]

Note: All inputs will be in lowercase. The order of your output does not matter.

Given two strings s and t, determine if they are isomorphic. Two strings are isomorphic if the characters in s can be replaced to get t. All occurrences of a character must be replaced with another character while preserving the order of characters. No two characters may map to the same character but a character may map to itself.

Example 1: Input: s = "egg", t = "add" Output: true

Example 2: Input: s = "foo", t = "bar" Output: false

Example 3: Input: s = "paper", t = "title" Output: true Note: You may assume both s and t have the same length.

Given a pattern and a string str, find if str follows the same pattern. Here follow means a full match, such that there is a bijection between a letter in pattern and a non-empty word in str.

Example 1: Input: pattern = "abba", str = "dog cat cat dog" Output: true

Example 2: Input:pattern = "abba", str = "dog cat cat fish" Output: false

Example 3: Input: pattern = "aaaa", str = "dog cat cat dog" Output: false

Example 4: Input: pattern = "abba", str = "dog dog dog dog" Output: false Notes: You may assume pattern contains only lowercase letters, and str contains lowercase letters that may be separated by a single space.