72. Edit Distance

public class EditDistance {
    public int minDistance(String word1, String word2) {
        int m = word1.length(), n = word2.length();
        int[][] dp = new int[m + 1][n + 1];
        for (int i = 0; i <= m; i++) {
            Arrays.fill(dp[i], Integer.MAX_VALUE);
            dp[i][0] = i;
        }

        for (int j = 0; j <= n; j++) {
            dp[0][j] = j;
        }

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                if (word1.charAt(i) == word2.charAt(j)) {
                    dp[i + 1][j + 1] = dp[i][j];
                } else {
                    dp[i + 1][j + 1] = Math.min(dp[i + 1][j], Math.min(dp[i][j + 1], dp[i][j])) + 1;
                }
            }
        }

        return dp[m][n];
    }
}