Sync LeetCode submission Runtime - 66 ms (18.23%), Memory - 15.3 MB (100.00%)

Author: jimit105

0800-letter-case-permutation/README.md

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+<p>Given a string <code>s</code>, you&nbsp;can transform every letter individually to be lowercase or uppercase to create another string.</p>
+
+<p>Return <em>a list of all possible strings we could create</em>. Return the output in <strong>any order</strong>.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> s = &quot;a1b2&quot;
+<strong>Output:</strong> [&quot;a1b2&quot;,&quot;a1B2&quot;,&quot;A1b2&quot;,&quot;A1B2&quot;]
+</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> s = &quot;3z4&quot;
+<strong>Output:</strong> [&quot;3z4&quot;,&quot;3Z4&quot;]
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= s.length &lt;= 12</code></li>
+	<li><code>s</code> consists of lowercase English letters, uppercase English letters, and digits.</li>
+</ul>

0800-letter-case-permutation/solution.py

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+# Approach 1 - Backtracking
+
+class Solution:
+    def letterCasePermutation(self, s: str) -> List[str]:
+        res = []
+        
+        def backtrack(sub = '', i = 0):
+            if len(sub) == len(s):
+                res.append(sub)
+            else:
+                if s[i].isalpha():
+                    backtrack(sub + s[i].swapcase(), i + 1)
+                backtrack(sub + s[i], i + 1)
+            
+        backtrack()
+        return res
+