feat: [Week 08-4] solve common longest subsequence

Author: Chaedie

longest-common-subsequence/Chaedie.py

@@ -0,0 +1,25 @@
+"""
+Solution: 재귀를 활용한 풀이, memo 를 활용한 시간복잡도 개선
+
+Time: O(m * n)
+Space: O(2 * m * n)
+"""
+
+
+class Solution:
+    def longestCommonSubsequence(self, text1: str, text2: str) -> int:
+        memo = {}
+
+        def dfs(i, j):
+            if (i, j) in memo:
+                return memo[(i, j)]
+
+            if i == len(text1) or j == len(text2):
+                memo[(i, j)] = 0
+            elif text1[i] == text2[j]:
+                memo[(i, j)] = 1 + dfs(i + 1, j + 1)
+            else:
+                memo[(i, j)] = max(dfs(i + 1, j), dfs(i, j + 1))
+            return memo[(i, j)]
+
+        return dfs(0, 0)