Feb 28

Author: siddydutta

2025-02-February-LeetCoding-Challenge/README.md

@@ -31,12 +31,12 @@
 | February 25 | [1524. Number of Sub-arrays With Odd Sum](https://leetcode.com/problems/number-of-sub-arrays-with-odd-sum/) | Medium | Solved |
 | February 26 | [1749. Maximum Absolute Sum of Any Subarray](https://leetcode.com/problems/maximum-absolute-sum-of-any-subarray/) | Medium | Unsolved |
 | February 27 | [873. Length of Longest Fibonacci Subsequence](https://leetcode.com/problems/length-of-longest-fibonacci-subsequence/) | Medium | Solved |
-| February 28 | []() |  |  |
+| February 28 | [](https://leetcode.com/problems/shortest-common-supersequence/) | Hard | Unsolved |
 
 
 ## Summary
 | Level  | Problems | Solved | Unsolved |
 | ---    | --- | --- | --- |
 | Easy   | 6 | 6 | 0 |
 | Medium | 19 | 14 | 5 |
-| Hard   | 1 | 1 | 0 |
+| Hard   | 2 | 1 | 1 |

2025-02-February-LeetCoding-Challenge/Shortest Common Supersequence .py

@@ -0,0 +1,31 @@
+class Solution:
+    def shortestCommonSupersequence(self, str1: str, str2: str) -> str:
+        l1, l2 = len(str1), len(str2)
+        prev_row = [str2[:col] for col in range(l2+1)]
+        for row in range(1, l1+1):
+            curr_row = [str1[:row]] + ([None]*l2)
+            for col in range(1, l2+1):
+                if str1[row-1] == str2[col-1]:
+                    curr_row[col] = prev_row[col-1] + str1[row-1]
+                else:
+                    p_s1 = prev_row[col]
+                    p_s2 = curr_row[col-1]
+                    curr_row[col] = (p_s1 + str1[row-1]
+                                     if len(p_s1) < len(p_s2)
+                                     else p_s2 + str2[col-1])
+            prev_row = curr_row
+        return prev_row[l2]
+
+
+def main():
+    str1 = 'abac'
+    str2 = 'cab'
+    assert Solution().shortestCommonSupersequence(str1, str2) == 'cabac'
+
+    str1 = 'bbbaaaba'
+    str2 = 'bbababbb'
+    assert Solution().shortestCommonSupersequence(str1, str2) == 'bbbaaababbb'
+
+
+if __name__ == '__main__':
+    main()