## 1657. Determine if Two Strings Are Close

Two strings are considered close if you can attain one from the other using the following operations:

• Operation 1: Swap any two existing characters.
• For example, `abcde -> aecdb`
• Operation 2: Transform every occurrence of one existing character into another existing character, and do the same with the other character.
• For example, `aacabb -> bbcbaa` (all `a`'s turn into `b`'s, and all `b`'s turn into `a`'s)

You can use the operations on either string as many times as necessary.

Given two strings, `word1` and `word2`, return `true` if `word1` and `word2` are close, and `false` otherwise.

Example 1:

```Input: word1 = "abc", word2 = "bca"
Output: true
Explanation: You can attain word2 from word1 in 2 operations.
Apply Operation 1: "abc" -> "acb"
Apply Operation 1: "acb" -> "bca"
```

Example 2:

```Input: word1 = "a", word2 = "aa"
Output: false
Explanation: It is impossible to attain word2 from word1, or vice versa, in any number of operations.
```

Example 3:

```Input: word1 = "cabbba", word2 = "abbccc"
Output: true
Explanation: You can attain word2 from word1 in 3 operations.
Apply Operation 1: "cabbba" -> "caabbb"
`Apply Operation 2: "`caabbb" -> "baaccc"
Apply Operation 2: "baaccc" -> "abbccc"
```

Example 4:

```Input: word1 = "cabbba", word2 = "aabbss"
Output: false
Explanation: It is impossible to attain word2 from word1, or vice versa, in any amount of operations.
```

Constraints:

• `1 <= word1.length, word2.length <= 105`
• `word1` and `word2` contain only lowercase English letters.

## Rust Solution

``````struct Solution;

use std::collections::HashMap;

impl Solution {
fn close_strings(word1: String, word2: String) -> bool {
let mut hm1: HashMap<char, usize> = HashMap::new();
let mut hm2: HashMap<char, usize> = HashMap::new();

for c in word1.chars() {
*hm1.entry(c).or_default() += 1;
}
for c in word2.chars() {
*hm2.entry(c).or_default() += 1;
}
let mut keys1: Vec<char> = hm1.keys().copied().collect();
let mut keys2: Vec<char> = hm2.keys().copied().collect();
keys1.sort_unstable();
keys2.sort_unstable();
let mut values1: Vec<usize> = hm1.values().copied().collect();
let mut values2: Vec<usize> = hm2.values().copied().collect();
values1.sort_unstable();
values2.sort_unstable();
keys1 == keys2 && values1 == values2
}
}

#[test]
fn test() {
let word1 = "abc".to_string();
let word2 = "bca".to_string();
let res = true;
assert_eq!(Solution::close_strings(word1, word2), res);
let word1 = "a".to_string();
let word2 = "aa".to_string();
let res = false;
assert_eq!(Solution::close_strings(word1, word2), res);
let word1 = "cabbba".to_string();
let word2 = "abbccc".to_string();
let res = true;
assert_eq!(Solution::close_strings(word1, word2), res);
let word1 = "cabbba".to_string();
let word2 = "aabbss".to_string();
let res = false;
assert_eq!(Solution::close_strings(word1, word2), res);
}
``````

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