Edit Distance

class Solution {
    public int minDistance(String word1, String word2) {
        int[][] dp = new int[word1.length()+1][word2.length()+1];
        for(int i = 0; i<dp.length; i++){
            for(int j = 0; j<dp[i].length; j++){
                if(i == 0){
                    dp[i][j] = j;
                }
                else if(j == 0){
                    dp[i][j] = i;
                }
                else 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][j-1], Math.min(dp[i-1][j], dp[i-1][j-1]))+1;
                }
            }
        }
        return dp[word1.length()][word2.length()];
    }
}