Short encoding of words

/*
 * A valid encoding of an array of words is any reference string s and array of indices indices such that:
 * words.length == indices.length
 * The reference string s ends with the '#' character.
 * For each index indices[i], the substring of s starting from indices[i] and up to (but not including) the next '#' character is equal to words[i].
 * Given an array of words, return the length of the shortest reference string s possible of any valid encoding of words.
 * Example 1:
 * Input: words = ["time", "me", "bell"]
 * Output: 10
 * Explanation: A valid encoding would be s = "time#bell#" and indices = [0, 2, 5].
 * words[0] = "time", the substring of s starting from indices[0] = 0 to the next '#' is underlined in "time#bell#"
 * words[1] = "me", the substring of s starting from indices[1] = 2 to the next '#' is underlined in "time#bell#"
 * words[2] = "bell", the substring of s starting from indices[2] = 5 to the next '#' is underlined in "time#bell#"
 * Example 2:
 * Input: words = ["t"]
 * Output: 2
 * Explanation: A valid encoding would be s = "t#" and indices = [0].
 * Constraints:
 * 1 <= words.length <= 2000
 * 1 <= words[i].length <= 7
 * words[i] consists of only lowercase letters.
 */
impl Solution {
  pub fn minimum_length_encoding(words: Vec<String>) -> i32 {
    use std::collections::HashSet;
    let mut set: HashSet<String> = words.into_iter().collect();
    let all: Vec<String> = set.iter().cloned().collect();
    for w in &all {
      for k in 1..w.len() {
        set.remove(&w[k..]);
      }
    }
    set.iter().map(|w| w.len() as i32 + 1).sum()
  }
}