Edit Distance

Problem page:https://leetcode.com/problems/edit-distance

Solution

class Solution:
    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(1, m + 1):
            dp[i][0] = i
        for i in range(1, n + 1):
            dp[0][i] = i
        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] = min(dp[i-1][j], dp[i][j - 1], dp[i-1][j - 1]) + 1
        return dp[m][n]

Complexity

• time: O(n * m)
• space: O(n * m)