- Longest Common Subsequence #274

Author: ayosecu

longest-common-subsequence/ayosecu.py

@@ -0,0 +1,31 @@
+class Solution:
+    """
+        - Time Complexity: O(mn), m = len(text1), n = len(text2)
+        - Space Complexity: O(mn), The size of the dp variable
+    """
+    def longestCommonSubsequence(self, text1: str, text2: str) -> int:
+        m, n = len(text1), len(text2)
+        dp = [ [0] * (n + 1) for _ in range(m + 1) ]
+
+        for i in range(m):
+            for j in range(n):
+                if text1[i] == text2[j]:
+                    # if matched, increase length
+                    dp[i + 1][j + 1] = dp[i][j] + 1
+                else:
+                    # if unmatched, select a larger length from left and up position
+                    dp[i + 1][j + 1] = max(dp[i + 1][j], dp[i][j + 1])
+        
+        return dp[m][n]
+
+
+tc = [
+        ("abcde", "ace", 3),
+        ("abc", "abc", 3),
+        ("abc", "def", 0) 
+]
+
+sol = Solution()
+for i, (s1, s2, e) in enumerate(tc, 1):
+    r = sol.longestCommonSubsequence(s1, s2)
+    print(f"TC {i} is Passed!" if r == e else f"TC {i} is Failed! - Expected: {e}, Result: {r}")