LeetCode 72 Edit Distance - Implementation

Classic edit distance DP.

def minDistance(word1, word2): 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][j - 1], dp[i - 1][j], dp[i - 1][j - 1])

return dp[m][n]

$O(m \times n)$ time and space.