Leetcode 72. Edit Distance

Seawolf

Given two words word1 and word2, find the minimum number of operations required to convert word1 to word2.

You have the following 3 operations permitted on a word:

Insert a character
Delete a character
Replace a character
Example 1:

Input: word1 = "horse", word2 = "ros"
Output: 3
Explanation:
horse -> rorse (replace 'h' with 'r')
rorse -> rose (remove 'r')
rose -> ros (remove 'e')
Example 2:

Input: word1 = "intention", word2 = "execution"
Output: 5
Explanation:
intention -> inention (remove 't')
inention -> enention (replace 'i' with 'e')
enention -> exention (replace 'n' with 'x')
exention -> exection (replace 'n' with 'c')
exection -> execution (insert 'u')

1. class Solution:
   
2.     def minDistance(self, word1: str, word2: str) -> int:
   
3.         m = len(word1)
   
4.         n = len(word2)
   
5.         dp = [[0 for _ in range(n + 1)] for _ in range(m + 1)]
   
6.         
   
7.         for i in range(1, m + 1):
   
8.             dp[i][0] = i
   
9.         
   
10.         for i in range(1, n + 1):
    
11.             dp[0][i] = i
    
12.         
    
13.         
    
14.         for i in range(1, m + 1):
    
15.             for j in range(1, n + 1):
    
16.                 if word1[i - 1] == word2[j - 1]:
    
17.                     dp[i][j] = dp[i - 1][j - 1]
    
18.                 else:
    
19.                     dp[i][j] = min(dp[i - 1][j], dp[i][j - 1], dp[i - 1][j - 1]) + 1
    
20.         return dp[m][n]

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