Problem: String Matching in an Array

You are given an array of strings words. Your task is to find all the strings in the array that are a substring of another string in the same array. Return these strings in any order.

Key Points:

• A substring is a part of another string. For example, "as" is a substring of "mass".
• We are looking for strings in the array that can be found as substrings within other strings in the array.

Examples:

Example 1:

Input:
words = ["mass", "as", "hero", "superhero"]
Output:
["as", "hero"]
Explanation:

• "as" is a substring of "mass".
• "hero" is a substring of "superhero".
• The order of the output does not matter. For example, ["hero", "as"] is also correct.

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Example 2:

Input:
words = ["leetcode", "et", "code"]
Output:
["et", "code"]
Explanation:

• "et" is a substring of "leetcode".
• "code" is a substring of "leetcode".

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Example 3:

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

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Constraints:

$$\begin{aligned} &1 \leq \text{words.length} \leq 100 \\ &1 \leq \text{words[i].length} \leq 30 \\ &\text{Each string in words contains only lowercase English letters.} \\ &\text{All strings in words are unique.} \end{aligned}$$

What to Do:

1. Go through each string in the array.
2. Check if it is a substring of any other string in the array.
3. Collect all such strings and return them in any order.

Output:

The output is an array containing strings that are substrings of other strings in the input array.