49. Group Anagrams

Given an array of strings `strs`, group the anagrams together. You can return the answer in any order.

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

Example 1:

```Input: strs = ["eat","tea","tan","ate","nat","bat"]
Output: [["bat"],["nat","tan"],["ate","eat","tea"]]
```

Example 2:

```Input: strs = [""]
Output: [[""]]
```

Example 3:

```Input: strs = ["a"]
Output: [["a"]]
```

Constraints:

• `1 <= strs.length <= 104`
• `0 <= strs[i].length <= 100`
• `strs[i]` consists of lower-case English letters.

49. Group Anagrams
``````struct Solution;

use std::collections::HashMap;

impl Solution {
fn group_anagrams(strs: Vec<String>) -> Vec<Vec<String>> {
let mut group_hm: HashMap<Vec<char>, Vec<String>> = HashMap::new();
for s in strs {
let mut v: Vec<char> = s.chars().collect();
v.sort_unstable();
let group = group_hm.entry(v).or_default();
group.push(s);
}
let mut res: Vec<Vec<String>> = vec![];
for (_, mut v) in group_hm {
v.sort();
res.push(v.to_vec());
}
res.sort_by_key(|x| x.len());
res
}
}

#[test]
fn test() {
let strs = vec_string!["eat", "tea", "tan", "ate", "nat", "bat"];
let res = vec_vec_string![["bat"], ["nat", "tan"], ["ate", "eat", "tea"]];
assert_eq!(Solution::group_anagrams(strs), res);
}
``````