Time: 40 ms (45.85%), Space: 13.6 MB (85.54%) - LeetHub

14-longest-common-prefix/14-longest-common-prefix.py

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+class Solution(object):
+    def longestCommonPrefix(self, strs):
+        """
+        :type strs: List[str]
+        :rtype: str
+        """
+        # Base len(strs) = 1 case:
+        if len(strs) == 1:
+            return strs[0]
+        
+        # Case len(strs) >= 2
+        currentLCP = self.lcpPair(strs[0], strs[1])
+        for i in range(2, len(strs)):
+            # All 0-i strings have no common prefix, thus neither will 0-n
+            if currentLCP == "":
+                return ""
+            
+            # Refine currentLCP to include the i'th element
+            currentLCP = self.lcpPair(currentLCP, strs[i])
+        
+        return currentLCP
+    
+    # Finds the longest common prefix of two strings
+    def lcpPair(self, s1, s2):
+        commonPrefixLength = 1
+        while s1[:commonPrefixLength] == s2[:commonPrefixLength] and commonPrefixLength <= min(len(s1), len(s2)):
+            commonPrefixLength += 1
+        return s1[:(commonPrefixLength - 1)]
+