力扣第72题 编辑距离

力扣第72题 编辑距离

class Solution {
    public:
    int minDistance(string word1, string word2) 
    {
        int len1 = word1.size();
        int len2 = word2.size();
        if (len1*len2 == 0)
            return len1 + len2;
        vector<vector<int>> dp(len1 + 1, vector<int>(len2 + 1));
        // 边界情况处理
        for (int i = 0; i <= len1; i++)
        {
            dp[i][0] = i;
        }
        for (int i = 0; i <= len2; i++)
        {
            dp[0][i] = i;
        }

        int left, down, left_down;
        for (int i = 1; i <= len1; i++)
        {
            for (int j = 1; j <= len2; j++)
            {
                left = dp[i - 1][j] + 1;
                down = dp[i][j - 1] + 1;
                left_down = dp[i - 1][j - 1];
                if (word1[i - 1] != word2[j - 1])
                    left_down += 1;
                dp[i][j] = min(min(left, down), left_down);
            }
        }
        return dp[len1][len2];
    }
};