daily

Author: Zanger67

my-submissions/h1092.py

@@ -0,0 +1,36 @@
+class Solution:
+    def shortestCommonSupersequence(self, str1: str, str2: str) -> str:
+        dp = [[i for i in range(len(str1) + 1)]] + \
+             [[i] + [None] * len(str1) for i in range(1, 1 + len(str2))]
+        dp[0][0] = 0
+
+        for i, ci in enumerate(str2, 1) :
+            for j, cj in enumerate(str1, 1) :
+                dp[i][j] = min(
+                        dp[i - 1][j], 
+                        dp[i][j - 1],
+                        dp[i - 1][j - 1] if ci == cj else inf   # if same letter
+                    ) + 1
+
+        output = []
+        r, c = len(dp) - 1, len(dp[0]) - 1
+
+        while r > 0 and c > 0 :
+            if dp[r][c] == dp[r - 1][c - 1] + 1 and str1[c - 1] == str2[r - 1]:
+                c -= 1
+                r -= 1
+                output.append(str1[c])
+                continue
+
+            if dp[r][c - 1] == dp[r][c] - 1 :
+                c -= 1
+                output.append(str1[c])
+                continue
+
+            r -= 1
+            output.append(str2[r])
+
+        output.extend((reversed(str1[:c])))
+        output.extend((reversed(str2[:r])))
+
+        return ''.join(reversed(output))