<p>You are given an array <code>arr</code> of size <code>n</code> consisting of <strong>non-empty</strong> strings.</p>

<p>Find a string array <code>answer</code> of size <code>n</code> such that:</p>

<ul>
	<li><code>answer[i]</code> is the <strong>shortest</strong> <span data-keyword="substring">substring</span> of <code>arr[i]</code> that does <strong>not</strong> occur as a substring in any other string in <code>arr</code>. If multiple such substrings exist, <code>answer[i]</code> should be the <span data-keyword="lexicographically-smaller-string">lexicographically smallest</span>. And if no such substring exists, <code>answer[i]</code> should be an empty string.</li>
</ul>

<p>Return <em>the array </em><code>answer</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> arr = [&quot;cab&quot;,&quot;ad&quot;,&quot;bad&quot;,&quot;c&quot;]
<strong>Output:</strong> [&quot;ab&quot;,&quot;&quot;,&quot;ba&quot;,&quot;&quot;]
<strong>Explanation:</strong> We have the following:
- For the string &quot;cab&quot;, the shortest substring that does not occur in any other string is either &quot;ca&quot; or &quot;ab&quot;, we choose the lexicographically smaller substring, which is &quot;ab&quot;.
- For the string &quot;ad&quot;, there is no substring that does not occur in any other string.
- For the string &quot;bad&quot;, the shortest substring that does not occur in any other string is &quot;ba&quot;.
- For the string &quot;c&quot;, there is no substring that does not occur in any other string.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> arr = [&quot;abc&quot;,&quot;bcd&quot;,&quot;abcd&quot;]
<strong>Output:</strong> [&quot;&quot;,&quot;&quot;,&quot;abcd&quot;]
<strong>Explanation:</strong> We have the following:
- For the string &quot;abc&quot;, there is no substring that does not occur in any other string.
- For the string &quot;bcd&quot;, there is no substring that does not occur in any other string.
- For the string &quot;abcd&quot;, the shortest substring that does not occur in any other string is &quot;abcd&quot;.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>n == arr.length</code></li>
	<li><code>2 &lt;= n &lt;= 100</code></li>
	<li><code>1 &lt;= arr[i].length &lt;= 20</code></li>
	<li><code>arr[i]</code> consists only of lowercase English letters.</li>
</ul>

class Solution:
    def substrings(self, s):
        # return the substrings of s
        substrings = [] 
        def backtracking(start, s, substrings):
            for i in range(start + 1, len(s) + 1):
                current_substring = s[start:i]
                
                # Exclude the full string itself
                #if current_substring != s:
                substrings.append(current_substring)
    
        for i in range(len(s)):
            backtracking(i, s, substrings)
        return sorted(substrings, key=lambda x: (len(x), x))

        
    def shortestSubstrings(self, arr: List[str]) -> List[str]:
        substrings_table = {}
        for s in arr:
            substrings_table[s] = self.substrings(s)
        print(substrings_table)
        result = ["" for _ in range(len(arr))]
        arr_counter = Counter(arr)
        for i, s in enumerate(arr):
            if arr_counter[s] > 1:
                continue
            print(f"currently processing {s}")
            for substring in substrings_table[s]:
                print(substring)
                for t in [x for x in arr if x!= s]:
                    if s != t: 
                        if substring not in substrings_table[t]:
                            continue
                        else:
                            print(f"{substring} in the substring of {t}")
                            break
                else:
                    print(f"find the first uncommon substring: {substring}, assign it to the result")
                    result[i] = substring
                    break
        return result

        
17600