1408. String Matching in an Array

Description

Given an array of string words, return all strings in words that is a substring of another word. You can return the answer in any order.

A substring is a contiguous sequence of characters within a string

 

Example 1:

Input: words = ["mass","as","hero","superhero"]
Output: ["as","hero"]
Explanation: "as" is substring of "mass" and "hero" is substring of "superhero".
["hero","as"] is also a valid answer.

Example 2:

Input: words = ["leetcode","et","code"]
Output: ["et","code"]
Explanation: "et", "code" are substring of "leetcode".

Example 3:

Input: words = ["blue","green","bu"]
Output: []
Explanation: No string of words is substring of another string.

 

Constraints:

• 1 <= words.length <= 100
• 1 <= words[i].length <= 30
• words[i] contains only lowercase English letters.
• All the strings of words are unique.

 

Solutions

Solution: Brute Force

• Time complexity: O(n²)
• Space complexity: O(n)

 

JavaScript

/**
 * @param {string[]} words
 * @return {string[]}
 */
const stringMatching = function (words) {
  const n = words.length;
  const memo = [];
  const result = new Set();

  words.sort((a, b) => b.length - a.length);

  for (const word of words) {
    for (const memoWord of memo) {
      if (word.length === memoWord.length || !memoWord.includes(word)) continue;

      result.add(word);
    }
    memo.push(word);
  }
  return [...result];
};