Create SolutionBySai.py

Dynamic Programming/Edit Distance/SolutionBySai.py

@@ -0,0 +1,29 @@
+class Solution:
+    def minDistance(self, word1: str, word2: str) -> int:
+        m = len(word1)
+        n = len(word2)
+
+        # initialise
+        dp = [[0]*(n+1) for i in range(m+1)]
+        dp[m][n] = 0
+        for i in range(m):
+            dp[i][n] = m - i
+        for i in range(n):
+            dp[m][i] = n - i
+
+        for i in range(m-1, -1, -1):
+            for j in range(n-1, -1, -1):
+                # same char
+                if word1[i] == word2[j]:
+                    dp[i][j] = dp[i+1][j+1]
+                else:
+                    dp[i][j] = 1 + dp[i+1][j+1]
+
+                # insertion
+                dp[i][j] = min(dp[i][j], 1 + dp[i][j+1])
+                # deletion
+                dp[i][j] = min(dp[i][j], 1 + dp[i+1][j])
+
+        return dp[0][0]
+
+