Given two wordsword1andword2, find the minimum number of steps required to convertword1toword2. (each operation is counted as 1 step.)

You have the following 3 operations permitted on a word:

a) Insert a character
b) Delete a character
c) Replace a character

class Solution {
    public int minDistance(String word1, String word2) {
        int n = word1.length(), m = word2.length();
        int[][] dp = new int[n + 1][m + 1];

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

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

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

        return dp[n][m];
    }
}