feat(work): add Minimum Path Sum & Longest Common Subsequence solutions; refactor Unique Paths DP implementation

work/1/Medium/String/1143.longest-common-subsequence.py

@@ -0,0 +1,63 @@
+"""
+1143. Longest Common Subsequence
+Difficulty: Medium
+https://leetcode.com/problems/longest-common-subsequence/
+
+──────────────────────────────────────────────────
+
+Given two strings text1 and text2, return the length of their longest
+common subsequence. If there is no common subsequence, return 0.
+
+A subsequence of a string is a new string generated from the original
+string with some characters (can be none) deleted without changing the
+relative order of the remaining characters.
+
+        • For example, "ace" is a subsequence of "abcde".
+
+A common subsequence of two strings is a subsequence that is common
+to both strings.
+
+
+
+Example 1:
+
+Input: text1 = "abcde", text2 = "ace"
+Output: 3
+Explanation: The longest common subsequence is "ace" and its length
+is 3.
+
+Example 2:
+
+Input: text1 = "abc", text2 = "abc"
+Output: 3
+Explanation: The longest common subsequence is "abc" and its length
+is 3.
+
+Example 3:
+
+Input: text1 = "abc", text2 = "def"
+Output: 0
+Explanation: There is no such common subsequence, so the result is 0.
+
+
+
+Constraints:
+
+        • 1 <= text1.length, text2.length <= 1000
+
+        • text1 and text2 consist of only lowercase English characters.
+"""
+
+
+class Solution:
+    def longestCommonSubsequence(self, text1: str, text2: str) -> int:
+        dp = [[0 for j in range(len(text2) + 1)] for i in range(len(text1) + 1)]
+
+        for i in range(len(text1) - 1, -1, -1):
+            for j in range(len(text2) - 1, -1, -1):
+                if text1[i] == text2[j]:
+                    dp[i][j] = 1 + dp[i + 1][j + 1]
+                else:
+                    dp[i][j] = max(dp[i][j + 1], dp[i + 1][j])
+
+        return dp[0][0]