Learning On the Way

72. Edit Distance

Given two strings word1 and word2, return the minimum number of operations required to convert word1 to word2. You have the following three operations permitted on a word:

• Insert a character
• Delete a character
• Replace a character

This is Levenshtein distance (https://en.wikipedia.org/wiki/Levenshtein_distance)

def minDistance(self, word1: str, word2: str) -> int: 
    m, n = len(word1), len(word2) 
        
    dp = [[0] * (n + 1) for _ in range(m + 1)] 
        
    for i in range(m + 1): 
        dp[i][0] = i 
            
    for j in range(n + 1): 
        dp[0][j] = j 
                
    for i in range(1, m + 1): 
        for j in range(1, n + 1): 
            if word1[i - 1] == word2[j - 1]: 
                dp[i][j] = dp[i - 1][j - 1] 
            else: 
                dp[i][j] = 1 + min(dp[i - 1][j - 1], dp[i][j - 1], dp[i - 1][j]) 
                    
    return dp[-1][-1]